Spectra free spectral range

The calculated ring resonator output spectrum in Fig. 9.16 is based on (9.9) and shows a series of resonance minima spaced at intervals known as the free spectral range A/.,.SR ... 

Frequency stabilisation and scanning is accomplished by use of a confocal cavity of free spectral range matched to the dye laser repetition rate. Phase modulated sidebands are put on to the mode spectrum of the mode-locked pulse train and used to lock the laser to the reference cavity. The frequency modulation technique is also used to lock the ultra-violet enhancement cavity to the mode-locked pulse train. 

Figure 9. Brillouin spectrum of commercial Mylar film at larger free-spectral range than in Figure 8...

A confocal FPI shall be used as optical spectrum analyzer, with a free spectral range of 3 GHz. Calculate the mirror separation d and the finesse that is necessary to resolve spectral features in the laser output within 10 MHz. What is the minimum reflectivity R of the mirrors, if the surface finesse is 500 ... 

Equation (5.49) reveals that the frequency spectrum of the confocal resonator is degenerate because the transverse modes with q = q and m- -n = 2p have the same frequency as the axial mode with m = n = 0 and q = q - -p. Between two axial modes there is always another transverse mode with m- -n -f 1 = odd. The free spectral range of a confocal resonator is therefore... 

Fig. 5. Polarized Rayleigh-Brillouin spectrum of amorphous PnHMA taken with a Burleigh plane Fabry-Perot interferometer using a free spectral range of 12.4 GHz at 295 K. The two Brillouin peaks are shifted from the incident frequency by the product of the wave vector q and the sound velocity u. The line width of the Brillouin peaks is related to the attenuation of the sound waves. PnHMA.

The spectrum below is recorded in fluorescence from a collimated cesium atomic beam, excited on the D F transition by a single mode tunable dye laser. The D level is populated in cascade decay from the P state, which is excited with a broadband CW dye laser. The Fabry-Perot fringes at the bottom correspond to a free spectral range of 50 MHz. 

Fig.7.4a-c. Schematic diagram of a diode laser, (a) Injection laser structure. (b) Mode spectrum within the gain profile, (c) Mode hops of a quasi-continuously tunable cw Pb Sn Te diode laser in an He cryostat. The laser frequency is tuned by changing the diode current. The points correspond to the transmission maxima of an external Ge etalon with a free spectral range of 1.955 GHz [7.2]... 

In the time-domain detection of the vibrational coherence, the high-wavenumber limit of the spectral range is determined by the time width of the pump and probe pulses. Actually, the highest-wavenumber band identified in the time-domain fourth-order coherent Raman spectrum is the phonon band of Ti02 at 826 cm. Direct observation of a frequency-domain spectrum is free from the high-wavenum-ber limit. On the other hand, the narrow-bandwidth, picosecond light pulse will be less intense than the femtosecond pulse that is used in the time-domain method and may cause a problem in detecting weak fourth-order responses. 

A variety of analytical techniques were then used to verify that Cd(OH)2 was present in the solution when the complex Cd ratio was below the critical value (Re) but absent above it. Cd(OH)2 absorbs in the UV range of the spectrum, and spectral monitoring of Se-free solutions showed that it was present only below Rc. Light scattering by a blue laser also confirmed the presence of a heterogeneous phase below Rc but not above it. Similar XPS analyses to those employed by Rieke and Bentjen for CdS showed that Cd adsorbed on the glass substrate, immersed in Se-free solutions, only below Rc. This is seen in Table 3.1 Appreciable amounts of Cd (as Cd(OH)2) were seen only when the pH was sufficiently high and the complex Cd ratio relatively low. 

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