Single-mode lasers

Johnson A M and Shank C V 1989 Pulse compression in single-mode fibres—picoseconds to femtoseconds The Supercontinuum Laser Source ed R R Alfano (New York Springer) pp 399-449... 

Figure B2.5.17. (a) Time-dependent intensity / and redueed fluenee F/Fq for a single-mode CO2 laser pulse used in the IR laser photolysis of CF I. Fq is the total fluenee of the laser pulse, (b) VIS-REMPI iodine atom signals obtained with CO2 laser pulses of different fluenee (after [113]).

Figure 10-15. Output vs. input energy characteristic of our laser device. The horizontal dashed curve indicates the zero line. A clear laser threshold behavior at an excitation pulse energy ol 1.5 nJ is observed. Below the lasing threshold only isotropic phololuminesccncc is entitled. Above threshold the device emits low divergence single mode laser emission perpendicular to the surface, as schematically shown in the inset. The laser light is polarized parallel to the grating lines.

LED do not have sufficient power for single mode fiber applications which, because of the smaller cross-sections, require more powerful lasers. The CVD of LED and laser materials is described in Ch. 15. 

Figure 28. Return flux from the modeless laser in the D2 line versus the input power. Top to bottom spectral FWHM = 3 GHz, 4.5 GHz and I MHz single mode (Pique and Faiinotti, 2003).

Compilation of results. In order to reduce as much as possible the effects of possible sources of noise we were forced to fix some properties of passive and active optical components. Let us summarize what we have learned. The laser has the following properties A = 1064 nm, P > 10 W, single mode operation, w(0) 3 cm. The mirrors must have the following... 

The experimental set-up for the FCS measurement is illustrated schematically in Figure 8.6. A CW Ar laser (LGK7872M, LASOS lasertechnik GmbH) at 488 nm was coupled to a single mode optical fiber to isolate the laser device from an experimental table on which the confocal microscope system was constructed. This excitation laser light transmitted through the optical fiber was collimated with a pair of lenses, and then was guided into a microscope objective (lOOX, NA 1.35, Olympus). 

Yasuharu Suematsu, Katsumi Kishino, Shigehisa Aral, and Fumio Koyama, Dynamic Single-Mode Semiconductor Lasers with a Distributed Reflector W. T. Tsang, The Cleaved-Coupled-Cavity (C3) Laser... 

Figure 7.22 shows the microscopic image of a typical laser-induced micronotch on a single-mode fiber (Coming SMF-28e). The laser power was set to 10 W and the exposure duration was 300 ms. Figure 7.23 shows the interference spectra of MZIs with the length of 5,10, 20, and 40 mm, respectively. The typical interference... 

PC-board It was shown that a very small number of atoms can be detected by monitoring through single-mode optical fiber under strong resonant laser... 

Recently, even practically, single-mode lasing of a droplet has been reported for quantum dot doped droplets14, when the droplet diameter was sufficiently small and pump laser intensities were high enough as shown in Fig. 17.10. Interestingly, the... 

Fig. 17.10 Schafer et al.14 have observed single mode lasing from core shell CdSe/ZnS nano crystal quantum dots in a glycerine water mixture. The fluorescence spectrum (black line) showed clear peaks of WGM and single mode lasing (grey line) was observed for sufficiently small droplets ( 10 pm) and high pump laser intensities (53 mJ crrT2 in 10 ns pulses at 532 nm). Insert shows the droplet trapped between the electrodes. Reprinted from Ref. 14 with permission. 2008 American Chemical Society...

Figure 2.8 A schematic diagram of the gain spectral profile, G(v), of a laser transition (solid line), together with the axial resonator modes (dotted line) of a cavity in which the frequency separation between adjacent modes is A v. (a) Multimode and (b) single-mode operation. The frequencies of those modes for which the gain exceeds the losses have been marked.

Usually, mainly Doppler broadening determines the gain profile of a particular laser transition. Indeed, due to the different configurations achievable with gas lasers (namely, a large cavity length), the laser line can be narrower than the Doppler linewidth. Different experimental realizations of single-mode lasers are detailed elsewhere (Demtroder, 2(X)3). 

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