당신은 주제를 찾고 있습니까 “stabilized helium neon laser – Helium-Neon Laser“? 다음 카테고리의 웹사이트 https://ro.taphoamini.com 에서 귀하의 모든 질문에 답변해 드립니다: ro.taphoamini.com/wiki. 바로 아래에서 답을 찾을 수 있습니다. 작성자 PHYWE Systeme GmbH \u0026 Co. KG 이(가) 작성한 기사에는 조회수 31,714회 및 좋아요 128개 개의 좋아요가 있습니다.
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stabilized helium neon laser 주제에 대한 동영상 보기
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d여기에서 Helium-Neon Laser – stabilized helium neon laser 주제에 대한 세부정보를 참조하세요
Principle: The difference between spontaneous and stimulated emission of light is demonstrated. The beam propagation within the resonator cavity of a He- Ne laser and its divergence are determined, its stability criterion is checked and the relative output power of the laser is measured as a function of the tube’s position inside the resonator and of the tube current.\r
What you can learn about:\r
* Spontaneous and stimulated light emission * Inversion * Collision of second type * Gas discharge tube * Resonator cavity * Transverse and longitudinal resonator modes * Birefringence * Brewster angle * Littrow prism * Fabry Perot Etalon
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Stabilized Helium-Neon Lasers – Research Electro-Optics
Stabilized Helium-Neon Lasers · Laser can be operated in either stable-frequency or stable-intensity operation mode. · TEM00 mode structure · Long term frequency …
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Date Published: 4/14/2022
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Stabilized helium-neon laser – SpringerLink
The results so far obtained indicate that the laser stabilized by the suggested method can be used as a secondary radiation source in interference measurem.
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Stabilized Helium Neon Laser Systems
Melles Griot stabilized helium neon lasers use two different stabilization techniques. The comparison method (aka frequency stabilization) is best when long- …
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주제와 관련된 이미지 stabilized helium neon laser
주제와 관련된 더 많은 사진을 참조하십시오 Helium-Neon Laser. 댓글에서 더 많은 관련 이미지를 보거나 필요한 경우 더 많은 관련 기사를 볼 수 있습니다.
주제에 대한 기사 평가 stabilized helium neon laser
- Author: PHYWE Systeme GmbH \u0026 Co. KG
- Views: 조회수 31,714회
- Likes: 좋아요 128개
- Date Published: 2010. 12. 16.
- Video Url link: https://www.youtube.com/watch?v=dSVLKzBVgc8
What is the frequency of a helium neon laser?
Our 633 nm Frequency/Intensity Stabilized Helium-Neon Lasers use a highly refined thermal compensation technique to provide an excellent balance of high output power and stability, low temperature sensitivity, and reliability.
How many levels are there in helium neon laser?
This gas laser is a four-level laser that use helium atoms to excite neon atoms. It is the atomic transitions in the neon that produces the laser light. The most commonly used neon transition in these lasers produces red light at 632.8 nm.
What is the standard value of red Colour wavelength in he Ne gas laser?
The best-known and most widely used He-Ne laser operates at a wavelength of 632.8 nm, in the red part of the visible spectrum.
What are three types of lasers?
- Gas Lasers.
- Solid-State Lasers.
- Fiber Lasers.
- Liquid Lasers (Dye Lasers)
- Semiconductor Lasers (Laser Diodes)
What are the advantages of He-Ne laser?
The advantages of helium-neon lasers are that they can emit visible light, are affordable and have good beam quality. While most lasers cannot efficiently emit visible light, helium-neon lasers usually emit at 632.8nm, producing a red beam.
What are the disadvantages of helium-neon laser?
Drawbacks or disadvantages of He-Ne Laser
➨Its output power is lower. ➨It is a low gain device. ➨In order to have operation at single wavelength, the other two wavelengths are required to be suppressed. This requires use of special techniques and extraordinary skills.
How powerful is a helium-neon laser?
The generated light has a wavelength of 632.8 nm with an output power range of 5–50 mW in a He-Ne laser, and wavelengths of 488 and 514.5 nm with an output power of 50–400 mW in an Ar-ion laser.
Which laser is having highest efficiency?
With 450 W quasi-CW stacked laser diode bars pumping at 1064 nm, 236 W optimum output laser at 1064 nm was obtained. The optical-to-optical conversion efficiency was 52.5% and corresponding slope efficiency was 62%. This is up to now the highest slope-efficiency acquired in high power Nd:YAG ceramic laser.
Which pumping is used in He-Ne laser?
Which pumping method is used in He-Ne laser? Explanation: Generally, in He-Ne laser, an electric discharge is used to excite the atoms of the active medium. This process is known as Electrical Excitation and is normally used in gas lasers.
Why He-Ne laser is better than ruby laser?
Ruby laser requires high power pumping source, whereas Helium-neon laser requires low power pumping source like electric discharge. Efficiency of helium-neon laser is more than ruby laser. The defects due to crystalline imperfections are also present in the ruby laser.
What is the output of He-Ne laser?
The He-Ne laser is a relatively low power device with an output in the visible red portion of the spectrum. The most common wavelength produced by He-Ne lasers is 632.8nm, although two lower power (1.152µm and 3.391µm) infrared wavelengths can be produced if desired.
What is the frequency of neon light?
Traditionally, fluorescent lamps have been operated at the same 50Hz or 60Hz frequency as the periodicity of the mains electricity supply.
What is the frequency of red laser light?
A red laser emits a very narrow beam at a wavelength of approximately 650 nm (650×10–9m), which corresponds to a frequency of approximately 4.61×1014 Hz, which is a few hundred terahertz! The typical emission spectrum of a red laser resembles that shown in Figure 1.
Which type of laser is helium neon laser?
…
Overview.
| Typical HeNe Parameters | |
|---|---|
| Transmission at Output Coupler (OC) | ~1% |
Stabilized Red HeNe Laser
Key Specifications Wavelength 632.992 nm (Vacuum) Stabilized Power >1.2 mW Polarization Linear >1000:1 Mode Structure TEM 00 > 99% Beam Diameter 0.65 ± 0.05 mm Beam Divergence 1.4 ± 0.2 mrad Beam Drift During Warm Up <0.2 mrad Long-Term Beam Drifta <0.02 mrad Power Input AC Universal 100 - 240 VAC, 50 - 60 Hz Lifetime (Typ.)b 25,000 h Time to Lockc <15 Minutes, Typical Temperature Range to Maintain Lock 15 - 30 °C Stabilization Specifications Output Frequency Stability in Frequency Stabilized Mode 1 Minute 1 Hour 8 Hours ±1 MHz ±2 MHz ±3 MHz Output Intensity Stability in Intensity Stabilized Mode 1 Minute 1 Hour 8 Hours ±0.1% ±0.2% ±0.3% Click for Dimensions This laser is shipped with a power supply with a universal voltage input. Features Center Wavelength: 632.992 nm Offers Two Stabilization Modes: Frequency or Intensity Output Power > 1.2 mW
Beam Diameter: 0.65 ± 0.05 mm
Linearly Polarized Output
Thorlabs’ Stabilized Helium Neon Laser, with a center wavelength of 632.992 nm, allows for either frequency or intensity stabilization, necessary for many spectroscopy, interferometry, and wavemeter applications. In frequency-stabilized mode, the laser will keep its lasing frequency (i.e., wavelength) constant, while in intensity-stabilized mode, the laser will keep its output power constant. For more details on the stabilization modes, please see the Stabilized HeNe tab. Under normal operating conditions, the lifetime of the HRS015B will be around 25,000 hours. The laser’s output is linearly polarized, with the polarization axis marked by a laser engraved line on the laser’s front face.
The graphs below show the stability of the laser in intensity-stabilized mode and frequency-stabilized mode. As seen in the graph on the left, the HRS015B laser’s power stabilizes significantly in less than 15 minutes of operation in intensity-stabilized mode and then reaches the final stabilized value in ~1 hour. If the power to the laser needs to be cycled after reaching stabilization in frequency-stabilized mode, the typical time to relock the laser is ~5 min, as shown in the graph on the right. Please note that the relock time depends on the shut down period as the laser will continue to cool while the power is off. Switching between these modes can be accomplished using the switch on the side of the laser housing, as seen in the Stabilized HeNe tab.
Please note that back reflections into the laser aperture will impair the ability of the control loop to stabilize the frequency or intensity of the laser. Furthermore, large amounts of back reflections can potentially disturb the population inversion of the laser, rendering it unable to lase properly. For instances where back reflections cannot be avoided, Thorlabs recommends using an optical isolator (for example, Item # IO-2D-633-VLP). Additionally, due to the significant ASE background, a bandpass filter should be used for precision measurements.
The laser is housed in a cylindrical tube, which can be conveniently mounted in a V-clamp mount such as Thorlabs’ C1513 Kinematic Mount. The Ø1.77″ tube is also compatible with our HCM2 HeNe Mount for 60 mm Cage Systems, as pictured above. For details on our assortment of HeNe accessories, please see the HeNe Accessories tab. The front bezel of this stabilized laser is internally SM1 (1.035″-40) threaded for compatibility with any of Thorlabs’ SM1-threaded components. The front face also includes an integrated beam stop and an industry-standard 4-40 tapped hole pattern compatible with our SM05AHN SM05-Threaded Adapter and HCL FiberPort Adapter. Please note that when attaching a FiberPort for collimation or coupling, the FiberPort must be intentionally misaligned by a small amount in order to avoid back reflections into the laser aperture.
Thorlabs also offers a 1532.8323 nm Frequency-Locked Laser that can be used as a wavelength reference source.
Click for Details
Click Here for Raw Data
The plot above shows the power fluctuations over an eight hour period in intensity-stabilized mode after a cold start. The fluctuations above represent the percent difference from the average power over the last four hours of measured data. Click on the graph to see a comparison between the power fluctations of the HRS015B and those of the former model. The plot above shows the power fluctuations over an eight hour period in intensity-stabilized mode after a cold start. The fluctuations above represent the percent difference from the average power over the last four hours of measured data. Click on the graph to see a comparison between the power fluctations of the HRS015B and those of the former model.
REO Precision Optical SolutionsREO Inc.
Stabilized Helium-Neon Lasers
For over 20 years, REO optimized optics and unique laser designs enable the highest quality, most reliable and broadest line of Helium Neon laser available. These include 633 nm Red (standard and high power models), 543 nm Green, 594 nm Yellow, 612 nm Orange, 1.15, 1.52 micron or 3.39 micron Infrared or our Multi-Line and Frequency/Intensity Stabilized lasers.
Our Frequency/Intensity Stabilized Laser at 632.8 nm applies superior thermal compensation resulting in an outstanding balance of high output power and stability with low temperature sensitivity and reliability. The stabilized laser is easily switched between the intensity and frequency stabilized operation. In the intensity stabilized mode, the laser can operate as an output power reference, with long-term intensity stability of < ±0.2% (1 hour). In the frequency stabilized mode, long term frequency stability is specified as 1.2 & >1.5 mW versions) from single line, 800:1 linearly polarized output
Greater than 100 m coherence length
CE compliant
OEM version available
When you need HeNe lasers renowned for their reliability, excellent lifetimes and resistance to retro-reflection…..
Stabilized HeNe Lasers
Our Stabilized HeNe Lasers are ideal for demanding applications in:
Interferometry
Precision metrology
Research
Excelitas’ REO Stabilized Helium-Neon Laser provides the benefits of active frequency and intensity stability together with exceptional ruggedness and long lifetime. Constructed using ultra-low loss optics manufactured in-house and our own unique cavity design, these lasers are guaranteed to deliver greater than 1.5 mW of single longitudinal mode, polarized output with frequency stabilization of ± 2 MHz (Frequency Mode) and intensity stabilization of ± 0.2% (Intensity Mode). With just the flick of a switch, customers can change between these two modes for maximum ease of use.
In addition to providing a technically superior laser, Excelitas offers the expertise and a collaborative approach to address the specific needs of our OEM customers including packaging, performance, functionality, delivery schedule and cost. Contact our team with any OEM or customization inquiries and we will work with you to provide the best possible laser solution for your application.
Iodine Stabilized Helium-Neon Laser
Iodine Stabilized Helium-Neon Laser
Primary Standard for Realization of the metre– iodine stabilized helium-neon laser
Photo of the SCL iodine stabilized HeNe laser Photo of the SCL iodine stabilized HeNe laser
The practical realization (“Mise en pratique”) of the definition of the metre, published by the CIPM in 1983, included the following methods:
length l travelled in vacuum by a plane electromagnetic wave in a time t, using l = c 0 ⋅t and c 0 = 299 792 458 m s–1, wavelength in vacuum of a plane electromagnetic wave of frequency ƒ, using λ = c 0 /ƒ and c 0 = 299 792 458 m s–1, by means of one of the radiations from a list, which is summarized in the graph below.
Secondary Representations of Second Secondary Representations of Second
The Consultative Committee of Length – Consultative Committee of Time and Frequency (CCL-CCTF) Frequency Standards Working Group is in charge of producing and maintaining the list of Recommended values of standard frequencies for application including the practical realization of the metre. Among the recommended frequencies, SCL has chosen 473.612 THz, corresponding to a wavelength of 633 nm, generated by an Iodine stabilized Helium-Neon Laser as its method of practical realization of the metre.
The 633 nm Iodine stabilized Helium-Neon Laser was the most classical standard frequency. Long before the last major change in the definition of metre that related the metre with the speed of light in 1983, Helium Neon laser was already one of the most popular research topics in the frequency metrology. Knowledge and techniques like the stabilization using iodine cell, 3rd derivative locking, saturated spectroscopy, etc. were developed in maintaining a high accuracy and stability of the frequency. Until the development of the frequency comb in around 2000, inter-laboratory comparison was developed by checking the beat frequency between different hyperfine components of the 633 nm laser frequency. For this historical reason, 633 nm frequency laser was used in many national metrology institutes (NMIs) as the practical realization of the metre.
To fulfil the requirement for the practical realization, the following conditions must be matched
cell-wall temperature (25 ± 5)°C;
cold-finger temperature (15.0 ± 0.2)°C;
frequency modulation width, peak-to-peak, (6.0 ± 0.3)MHz;
one-way intracavity beam power (10 ± 5) mW for an absolute value of the power shift coefficient ≤ 1.0kHz/mW.
With the above conditions and other necessary condition on the optical and electronic control systems including the use of the third harmonic detection technique and corresponding to the ƒ hyperfine component, the following values
ƒ = 473 612 353 604kHz
λ = 632 991 212.58 fm
with a relative standard uncertainty of 2.1 x 10-11 can be used.
Reference
frequency-stabilized red HeNe laser
OEM-Laser-Service
SIOS not only offers technically high-quality standard HeNe lasers, but also has the necessary expertise and competence to meet specific requirements of OEM customers. Our experts develop individual frequency-stabilized OEM laser modules adapted to your requirements in close consultation with you.
With pleasure we can:
optimize laser characteristics such as frequency stability, light output, thermal frequency drift, beam diameter and divergence, and mode spacing and polarization for your needs,
customize the installation criteria such as space requirements, power supply, connectivity or waste heat characteristics to increase maintainability,
take measures against electric shock, touch protection, overcurrent resistance, but also against critical environmental influences such as dust ingress (encapsulation),
for fiber-coupled OEM modules: Type and length of fiber, connectors on input and beam exit side, possibly provide free fiber end.
Through direct communication with our laser specialists, we can guarantee a speedy design process. Thanks to our own capacities in electronics manufacturing for frequency-stabilized He-Ne lasers, nothing stands in the way of the production of customer-specific OEM laser modules with a high degree of individualization. Effective processing and a lean company structure guarantee competitive costs.
Our service is rounded off by frequency recalibration of your lasers as well as laser tube exchange.
More information about our OEM solutions
Stabilized helium-neon laser
The results so far obtained indicate that the laser stabilized by the suggested method can be used as a secondary radiation source in interference measurements. Until more acceptable excitation conditions for the cell are obtained, the radiation wavelengths of such a source should be periodically checked against the isotope86Kr wavelength.
15.6: The Helium-Neon Laser
The He-Ne laser was the first continuous wave (cw) laser invented. A few months after Maiman announced his invention of the pulsed ruby laser, Ali Javan and his associates W. R. Bennet and D. R. Herriott announced their creation of a cw He-Ne laser. This gas laser is a four-level laser that use helium atoms to excite neon atoms. It is the atomic transitions in the neon that produces the laser light. The most commonly used neon transition in these lasers produces red light at 632.8 nm. But these lasers can also produce green and yellow light in the visible as well as UV and IR (Javan’s first He-Ne operated in the IR at 1152.3 nm). By using highly reflective mirrors designed for one of these many possible lasing transitions, a given He-Ne’s output is made to operate at a single wavelength.
He-Ne lasers typically produce a few to tens of mW (milli-Watt, or \(10^{-3}\) W) of power. They are not sources of high power laser light. Probably one of the most important features of these lasers is that they are highly stable, both in terms of their wavelength (mode stability) and intensity of their output light (low jitter in power level). For these reasons, He-Ne lasers are often used to stabilize other lasers. They are also used in applications, such as holography, where mode stability is important. Until the mid 1990’s, He-Ne lasers were the dominant type of lasers produced for low power applications – from range finding to scanning to optical transmission, to laser pointers, etc. Recently, however, other types of lasers, most notably the semiconductor lasers, seem to have won the competition because of reduced costs.
The above energy level diagram shows the two excited states of helium atom, the 2 3S and 2 1S, that get populated as a result of the electromagnetic pumping in the discharge. Both of these states are metastable and do not allow de-excitations via radiative transitions. Instead, the helium atoms give off their energy to neon atoms through collisional excitation. In this way the 4s and 5s levels in neon get populated. These are the two upper lasing levels, each for a separate set of lasing transitions. Radiative decay from the 5s to the 4s levels are forbidden. So, the 4p and 3p levels serve as the lower lasing levels and rapidly decay into the metastable 3s level. In this way population inversion is easily achieved in the He-Ne. The 632.8 nm laser transition, for example, involves the 5s and 3p levels, as shown above.
In most He-Ne lasers the gas, a mixture of 5 parts helium to 1 part neon, is contained in a sealed glass tube with a narrow (2 to 3 mm diameter) bore that is connected to a larger size tube called a ballast, as shown above. Typically the laser’s optical cavity mirrors, the high reflector and the output coupler, form the two sealing caps for the narrow bore tube. High voltage electrodes create a narrow electric discharge along the length of this tube, which then leads to the narrow beam of laser light. The function of the ballast is to maintain the desired gas mixture. Since some of the atoms may get imbedded in the glass and/or the electrodes as they accelerate within the discharge, in the absence of a ballast the tube would not last very long. To further prolong tube lifetime some of these lasers also use “getters”, often metals such as titanium, that absorb impurities in the gas.
Above photograph shows a commercial He-Ne tube. The thicker cylinder closest to the meter-stick (shown for scale) is the ballast. The thinner tube houses the resonant cavity where the lasing occurs. Notice the two mirrors that seal the two ends of the bore. For mode stability reasons, these mirrors are concave; they serve as the output coupler and the high reflector.
A typical commercially available He-Ne produces about a few mW of 632.8 nm light with a beam width of a few millimeters at an overall efficiency of near 0.1%. This means that for every 1 Watt of input power from the power supply, 1 mW of laser light is produced. Still, because of their long operating lifetime of 20,000 hours or more and their relatively low manufacturing cost, He-Ne lasers are among the most popular gas lasers.
Helium–neon laser
Type of gas laser
Helium–neon laser at the University of Chemnitz, Germany
A helium–neon laser or He-Ne laser, is a type of gas laser whose high energetic medium gain medium consists of a mixture of 10:1 ratio of helium and neon at a total pressure of about 1 torr inside of a small electrical discharge. The best-known and most widely used He-Ne laser operates at a wavelength of 632.8 nm, in the red part of the visible spectrum.
History of He-Ne laser development [ edit ]
The first He-Ne lasers emitted infrared at 1150 nm, and were the first gas lasers and the first lasers with continuous wave output. However, a laser that operated at visible wavelengths was much more in demand, and a number of other neon transitions were investigated to identify ones in which a population inversion can be achieved. The 633 nm line was found to have the highest gain in the visible spectrum, making this the wavelength of choice for most He-Ne lasers. However, other visible and infrared stimulated-emission wavelengths are possible, and by using mirror coatings with their peak reflectance at these other wavelengths; He-Ne lasers could be engineered to employ those transitions, including visible lasers appearing red, orange, yellow, and green.[1] Stimulated emissions are known from over 100 μm in the far infrared to 540 nm in the visible.
Because visible transitions have somewhat lower gain, these lasers generally have lower output efficiencies and are more costly. The 3.39 μm transition has a very high gain, but is prevented from use in an ordinary He-Ne laser (of a different intended wavelength) because the cavity and mirrors are lossy at that wavelength. However, in high-power He-Ne lasers having a particularly long cavity, superluminescence at 3.39 μm can become a nuisance, robbing power from the stimulated emission medium, often requiring additional suppression.
The best-known and most widely used He-Ne laser operates at a wavelength of 632.8 nm, in the red part of the visible spectrum. It was developed at Bell Telephone Laboratories in 1962,[2][3] 18 months after the pioneering demonstration at the same laboratory of the first continuous infrared He-Ne gas laser in December 1960.[4]
Construction and operation [ edit ]
The gain medium of the laser, as suggested by its name, is a mixture of helium and neon gases, in approximately a 10:1 ratio, contained at low pressure in a glass envelope. The gas mixture is mostly helium, so that helium atoms can be excited. The excited helium atoms collide with neon atoms, exciting some of them to the state that radiates 632.8 nm. Without helium, the neon atoms would be excited mostly to lower excited states, responsible for non-laser lines.
A neon laser with no helium can be constructed, but it is much more difficult without this means of energy coupling. Therefore, a He-Ne laser that has lost enough of its helium (e.g., due to diffusion through the seals or glass) will lose its laser functionality because the pumping efficiency will be too low.[5] The energy or pump source of the laser is provided by a high-voltage electrical discharge passed through the gas between electrodes (anode and cathode) within the tube. A DC current of 3 to 20 mA is typically required for CW operation. The optical cavity of the laser usually consists of two concave mirrors or one plane and one concave mirror: one having very high (typically 99.9%) reflectance, and the output coupler mirror allowing approximately 1% transmission.
Schematic diagram of a helium–neon laser
Commercial He-Ne lasers are relatively small devices, among gas lasers, having cavity lengths usually ranging from 15 to 50 cm (but sometimes up to about 1 meter to achieve the highest powers), and optical output power levels ranging from 0.5 to 50 mW.
The red He-Ne laser wavelength of 633 nm has an actual vacuum wavelength of 632.991 nm, or about 632.816 nm in air. The wavelengths of the stimulated emission modes lie within about 0.001 nm above or below this value, and the wavelengths of those modes shift within this range due to thermal expansion and contraction of the cavity. Frequency-stabilized versions enable the wavelength of a single mode to be specified to within 1 part in 108 by the technique of comparing the powers of two longitudinal modes in opposite polarizations.[6] Absolute stabilization of the laser’s frequency (or wavelength) as fine as 2.5 parts in 1011 can be obtained through use of an iodine absorption cell.[7]
Energy levels in a He-Ne Laser
Ring He-Ne Laser
The mechanism producing population inversion and light amplification in a He-Ne laser plasma[4] originates with inelastic collision of energetic electrons with ground-state helium atoms in the gas mixture. As shown in the accompanying energy-level diagram, these collisions excite helium atoms from the ground state to higher energy excited states, among them the 23S 1 and 21S 0 (LS, or Russell–Saunders coupling, front number 2 indicates that an excited electron is n = 2 state) are long-lived metastable states. Because of a fortuitous near-coincidence between the energy levels of the two He metastable states and the 5s 2 and 4s 2 ( Paschen notation[8]) levels of neon, collisions between these helium metastable atoms and ground-state neon atoms results in a selective and efficient transfer of excitation energy from the helium to neon. This excitation energy transfer process is given by the reaction equations
He*(23S 1 ) + Ne1S 0 → He(1S 0 ) + Ne*4s 2 + ΔE, He*(21S) + Ne1S 0 + ΔE → He(1S 0 ) + Ne*5s 2 ,
where * represents an excited state, and ΔE is the small energy difference between the energy states of the two atoms, of the order of 0.05 eV, or 387 cm−1, which is supplied by kinetic energy. Excitation-energy transfer increases the population of the neon 4s 2 and 5s 2 levels manyfold. When the population of these two upper levels exceeds that of the corresponding lower level, 3p 4 , to which they are optically connected, population inversion is present. The medium becomes capable of amplifying light in a narrow band at 1.15 μm (corresponding to the 4s 2 to 3p 4 transition) and in a narrow band at 632.8 nm (corresponding to the 5s 2 to 3p 4 transition). The 3p 4 level is efficiently emptied by fast radiative decay to the 3s state, eventually reaching the ground state.
The remaining step in utilizing optical amplification to create an optical oscillator is to place highly reflecting mirrors at each end of the amplifying medium so that a wave in a particular spatial mode will reflect back upon itself, gaining more power in each pass than is lost due to transmission through the mirrors and diffraction. When these conditions are met for one or more longitudinal modes, then radiation in those modes will rapidly build up until gain saturation occurs, resulting in a stable continuous laser-beam output through the front (typically 99% reflecting) mirror.
10 000 times narrower than the spectral width of a light-emitting diode (see Spectrum of a helium–neon laser illustrating its very high spectral purity (limited by the measuring apparatus). The 0.002 nm bandwidth of the stimulated emission medium is well overtimes narrower than the spectral width of a light-emitting diode (see its spectrum for comparison), with the bandwidth of a single longitudinal mode being much narrower still.
The gain bandwidth of the He-Ne laser is dominated by Doppler broadening rather than pressure broadening due to the low gas pressure and is thus quite narrow: only about 1.5 GHz full width for the 633 nm transition.[6][9] With cavities having typical lengths of 15 to 50 cm, this allows about 2 to 8 longitudinal modes to oscillate simultaneously (however, single-longitudinal-mode units are available for special applications). The visible output of the red He-Ne laser, long coherence length, and its excellent spatial quality, makes this laser a useful source for holography and as a wavelength reference for spectroscopy. A stabilized He-Ne laser is also one of the benchmark systems for the definition of the meter.[7]
Prior to the invention of cheap, abundant diode lasers, red He-Ne lasers were widely used in barcode scanners at supermarket checkout counters. Laser gyroscopes have employed He-Ne lasers operating at 633 nm in a ring laser configuration. He-Ne lasers are generally present in educational and research optical laboratories.
Applications [ edit ]
Red He-Ne lasers have an enormous number of industrial and scientific uses. They are widely used in laboratory demonstrations in the field of optics because of their relatively low cost and ease of operation compared to other visible lasers producing beams of similar quality in terms of spatial coherence (a single-mode Gaussian beam) and long coherence length (however, since about 1990 semiconductor lasers have offered a lower-cost alternative for many such applications).
Starting in 1978, HeNe tube lasers (manufactured by Toshiba and NEC) were used in Pioneer LaserDisc players. This continued until the 1984 model lineup, which contained infrared laser diodes instead. Pioneer continued to use laser diodes in all subsequent players until the format’s discontinuation in 2009.
See also [ edit ]
키워드에 대한 정보 stabilized helium neon laser
다음은 Bing에서 stabilized helium neon laser 주제에 대한 검색 결과입니다. 필요한 경우 더 읽을 수 있습니다.
이 기사는 인터넷의 다양한 출처에서 편집되었습니다. 이 기사가 유용했기를 바랍니다. 이 기사가 유용하다고 생각되면 공유하십시오. 매우 감사합니다!
사람들이 주제에 대해 자주 검색하는 키워드 Helium-Neon Laser
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Helium-Neon #Laser
YouTube에서 stabilized helium neon laser 주제의 다른 동영상 보기
주제에 대한 기사를 시청해 주셔서 감사합니다 Helium-Neon Laser | stabilized helium neon laser, 이 기사가 유용하다고 생각되면 공유하십시오, 매우 감사합니다.
