Diffraction Loss and Selection of Modes in Maser Resonators with Circular Mirrors

Li, Tingye

doi:10.1002/j.1538-7305.1965.tb04164.x

Cited by 173 publications

(25 citation statements)

References 10 publications

(7 reference statements)

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“…To maximize the returned probe SNR, the probe beam is focused on the retroreflector with a transceiver dish whose focal length f=# ¼ R=D tr . The diffraction-limited Airy disk diameter of the transmitted probe at the retroreflector d t ¼ ð2.44λ pr f=#Þ may be compared with D rr to ascertain if the probe's optical system is confocal (d t < D rr or R < D tr D rr =2.44λ pr ), in which case virtually all the probe signal is returned to the transceiver (f tr ¼ 1) [25][26][27][28]. For D tr ¼ D rr ¼ 1 m, the probe system is confocal over an R ¼ 100-m range for wavelengths λ pr < 4.1 mm (ν pr > 73 GHz) and over an R ¼ 1-km range for wavelengths λ pr < 0.41 mm (ν pr > 730 GHz).…”

Section: A Probe Propagation In Clear Atmospherementioning

confidence: 99%

Design and Signature Analysis of Remote Trace-Gas Identification Methodology Based on Infrared-Terahertz Double-Resonance Spectroscopy

et al. 2014

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The practicality of a newly proposed infrared-terahertz (IR-THz) double-resonance (DR) spectroscopic technique for remote trace-gas identification is explored. The strength of the DR signatures depends on known molecular parameters from which a combination of pump-probe transitions may be identified to recognize a specific analyte. Atmospheric pressure broadening of the IR and THz trace-gas spectra relaxes the stringent pump coincidence requirement, allowing many DR signatures to be excited, some of which occur in the favorable atmospheric transmission windows below 500 GHz. By designing the DR spectrometer and performing a detailed signal analysis, the pump-probe power requirements for detecting trace amounts of methyl fluoride, methyl chloride, or methyl bromide may be estimated for distances up to 1 km. The strength of the DR signature increases linearly with pump intensity but only as the square root of the probe power because the received signal is in the Townes noise limit. The concept of a specificity matrix is introduced and used to quantify the recognition specificity and calculate the probability of false positive detection of an interferent.

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Section: A Probe Propagation In Clear Atmospherementioning

confidence: 99%

Design and Signature Analysis of Remote Trace-Gas Identification Methodology Based on Infrared-Terahertz Double-Resonance Spectroscopy

et al. 2014

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“…If two resonators have the same values of N, g 1 and g 2 , then they have the same diffraction loss, the same resonant frequency, and the same mode patterns. The fractional energy loss per transit due to diffraction effects for the lowest-order mode of a resonator with identical mirrors (g 1 = g 2 = g) is given by Li [15]. For the plane-parallel resonator with circular aperture, an analytical expression of the diffraction losses for large Fresnel numbers (F 1) has been derived by Vainshtein [16]:…”

Section: Diffraction Lossesmentioning

confidence: 99%

Study of Various Designs of Solid State Laser Oscillator

Semwal¹

2013

IOSRJEN

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-This study concerns with the laser oscillator, threshold conditions, circulating power, and the Gaussian beam profile. Laser oscillator is a crucial device, which provides the feedback necessary to make a laser work. The regenerative laser oscillator is essentially a combination of two basic components: an optical amplifier, and an optical resonator, which serves to provide highly selective feedback. The optical resonator, comprised of two opposing plane-parallel or curved mirrors at right angles to the axis of active material, performs function of the feedback element, by coupling back in phase a portion of the signal emerging from the amplifing medium. The photons are reflected back and forth for many passes through the rod (amplifying medium), stimulating more and more emission on each pass. The mirrors can be gently curved so they tend to keep the light concentration inside the rod. One of the mirrors is 100 % reflective, but the other mirror transmits part of the light hitting it. This transmitted light is the output beam from the laser

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“…TEM 00 selectivity, using either diffraction or aperature loss mechanisms, is greatest for a confocal or half-confocal resonator and smallest for a plane-parallel resonator [19], Although confocal and half-confocal resonators are on the edge of stability [20], near confocal or near half-confocal resonators are stable resonators and have also displayed more reliable mode-locking than plane-parallel resonators [7]. Therefore.…”

Section: Laser Cavitymentioning

confidence: 99%

Passively mode-locked Nd:glass laser oscillator optimized for TEM00 selectivity and long term stability and reliability

George

Harris

1981

Review of Scientific Instruments

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A passively mode-locked Nd:Glass laser oscillator optimized for TEM 00 selectivity and long term stability and reliability is presented.The important aspects of the optimized design are explained in detail.A detailed alignment procedure is also included. This laser oscillator is capable of producing TEM 00 • bandwidth-limited. 5 picosecond pulses for 12 hours.This manuscript was printed from originals provided by the author, "!" Introduction sively mode-locked Nd:Glass laser oscillators are used extensively as a of high pmver picosecond light pulses [1]. Limiting this laser oscillator I to tl1e TEM 00 transverse mode is desirable because the TEM 00 transverse mode produces a uniform and uniphase radial intensity profile, the smallest beam divergence, and t power density [2]. Unfortunately, passively mode~locked Nd:Glass "lasers res exclusively to TEM 00 operation are notoriously unstable, unreliable di cult to align,Although the generation and applications of passively mode-locked picosecond n pulses has been revievved [3,4] and passively mode-locked Nd:Glass picosecond pt,(lses have been studied [5,6], an optimized, detailed design for a stable, reliable and TEM 00 selective passively mode-locked Nd:Glass laser oscillator has never been presented, This is particularly unfortunate, because minute details can make extraordinary differences in the laser's performance [7 .8.9], Therefore, ~nowledge of a detailed design is extremely important to the user of TEM 00 selective, passively mode-locked Nd:Glass lasers.In this paper, we report on the design. operation, and performance of a passively mode-locked Nd:Glass laser oscillator which produces essentially bandwidth-limited 5 picosecond pulses and has been optimized for TEM 00 selectivity and long term s ility and reliability. We discuss the important aspects of the design in detail, with special emphasis on the reasons for the design, Because many of the design criteria are not limited to the passively mode-locked Nd:Glass laser, paper should also be usefu·l to i gners of other 1aser systems. In addition,we include a detailed alignment procedure because proper alignment is critical for s le 9 reliable and TEM 00 selective laser operation. 4, Lase HeadEfficient optical pumping is essential for minimal thermal distortions in the laser rod. In addition 9 uniform illumination of the laser rod is important for TEM 00 operation. Therefore. the laser head (see Fig. l) is a cloverleaf design machined from brass and electroplated with nickel and then gold to provide high reflectivity over almost all the Nd:Glass pumping bands [23], Four linear zenon r flashlamps are mounted slightly off the center of each cylindrical leaf in a close-coupled reflector design that provi uniform illumination of the rod. This allows a larger active volume of the laser rod to be utilized.Accurate-alignment is crucial for stable and reliable TEM 00 operation. For precise and easy alignment, the laser head sits in a stainless steel carriage which is attached to an adjustable stainless ste...

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Diffraction Loss and Selection of Modes in Maser Resonators with Circular Mirrors

Cited by 173 publications

References 10 publications

Design and Signature Analysis of Remote Trace-Gas Identification Methodology Based on Infrared-Terahertz Double-Resonance Spectroscopy

Design and Signature Analysis of Remote Trace-Gas Identification Methodology Based on Infrared-Terahertz Double-Resonance Spectroscopy

Study of Various Designs of Solid State Laser Oscillator

Passively mode-locked Nd:glass laser oscillator optimized for TEM00 selectivity and long term stability and reliability

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