Optical cavity-laser

B. Agate, B. Stormont, A.J. Kemp, C.T.A. Brown, U. Keller, and W. Sibbett, Simplified cavity designs for efficient and compact femtosecond Cr LiSAF lasers. Optics Communications 205,207-213 (2002). 

A major development reported in 1964 was the first numerical solution of the laser equations by Buley and Cummings [15]. They predicted the possibility of undamped chaotic oscillations far above a gain threshold in lasers. Precisely, they numerically found almost random spikes in systems of equations adopted to a model of a single-mode laser with a bad cavity. Thus optical chaos became a subject soon after the appearance Lorenz paper [2]. 

The cleaved-coupled-cavity laser developed by W.T. Tsang and colleagues (AT T Bell Laboratories) was designed especially for use in fiber optics telecommunication systems and probably as much as the optical fibers themselves will contribute to the gross claims, as mentioned earlier in the article, made for faster, higher-capacity optical links. 

FIGURE 3 Two distinct longitudinal modes occupying the same spatial region of the laser optical cavity. 

FIGURE 5 Laser output resulting from effects of laser amplifier gain bandwidth and laser optical cavity modes. 

A wide variety of laser optical systerrrs are errrployed to extract a beam from the cavity. Typical of these is the rrrrstable resonator in Fig. 5. In this systerrr, there is a central region near the optical axis (of such a raditts that its Fresnel nttmber is near rrrrity) within which all the laser radiation is closely coupled by diffraction. Therefore, the... 

Mode locked laser Optical oscillator in which the longitudinal cavity modes are locked in phase, generating a periodic (i.e., pulsed) optical output. 

The experimental scheme used in these experiments is quite simple in its principle (see Figure 1). The Rydberg atoms are prepared by laser excitation of an atomic beam. The laser radiation is attenuated until one makes sure that no more than one atom at a time is prepared in the cavity. The optical selection rules result in a preparation of low angular momentum Rydberg levels (practically s, p or d states with Jl = 0, 1 or 2 depending upon the number of photons involved in the optical transition). 

New absorption methods, like intracavity spectroscopy, cavity-ring-down and cavity-enhanced spectroscopy, have demonstrated very high sensitivities in laboratory measurements with DLs. An ultrasensitive technique that combines external cavity enhancement and FM spectroscopy has been developed recently. This method, which has been called NICE-OHMS. or noise-immune cavity-enhanced optical heterodyne molecular spectroscopy, is based on frequency modulation of the laser at the cavity free-spectral-range frequency or its multiple. The MDA of 5x 10 1 X 10 cm ) in the detection of narrow... 

Figure 9.14 Laser cavity of optical path length L augmented with an etalon, whose partially reflecting surfaces are separated by a precisely variable distance L. ...

We have now discussed different characteristics of laser light without dealing with its frequency distribution in detail. It is evident that a stable oscillation mode can be achieved in the resonator only if there is constant constructive interference, i.e. standing waves. This occurs when an integer number of half wavelengths fit into the cavity of (optical) pathlength t By considering two adjacent modes we obtain the mode separation Au... 

O Keefe A and Deacon DAG 1988 Cavity ring-down optical spectrometer for absorption-measurements using pulsed laser sources Rev. Sol. Instrum. 59 2544-51... 

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