Lead-salt tunable diode lasers

Linewldth Considerations and Lead-Salt Tunable Diode Lasers... 

For the visible and near-ultraviolet portions of the spectmm, tunable dye lasers have commonly been used as the light source, although they are being replaced in many appHcation by tunable soHd-state lasers, eg, titanium-doped sapphire. Optical parametric oscillators are also developing as useful spectroscopic sources. In the infrared, tunable laser semiconductor diodes have been employed. The tunable diode lasers which contain lead salts have been employed for remote monitoring of poUutant species. Needs for infrared spectroscopy provide an impetus for continued development of tunable infrared lasers (see Infrared technology and RAMAN spectroscopy). 

It would be premature, however, to conclude that the extremely narrow (20-30 kHz) linewidths achieved with broad-area, homojunction solitary PbSi xSex tunable diode lasers can be obtained with all other lead-salt compounds and diode structures as well. Figure 6 shows some of the most frequently used lead-salt semiconductors which can provide a class of tunable lasers with emission wavelengths anywhere between about 2 1/2 um and 30 um. The figure illustrates the dependence of laser wavelengths on composition of the lead-salt compounds. The lower left portion of the figure shows PbEuSeTe which can be used to cover the 2.6 to 6.6 pm wavelength range. This is a new material recently developed at the... 

C. Freed, J. W. Biellnskl, and W. Lo, "Programmable, Secondary Frequency Standard Based Infrared Synthesizer using Tunable Lead-Salt Diode Lasers," Proceedings of Tunable Diode Laser Development and Spectroscopy Applications," SPIE 438, (1983). 

Fig. 6. Emission wavelength range of various tunable lead-salt diode lasers.

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