Piezo-controlled intracavity wavelength selector for the far-infrared p-Ge laser

High-resolution study of composite cavity effects for p-Ge lasers

“…6 shows a spectrum of the p-Ge laser with tunable frequency selector (see Fig. 1 [6] was included in this cavity (Fig. 1).…”

“…1). Recently, it was discovered that the selection efficiency (active cavity finesse) strongly depends on the precise position of the tunable mirror [6]. For Fig.…”

Far-infrared p-Ge laser with variable length cavity

“…The p-Ge laser mechanism is based on intersubband transitions of hot holes [1], where an inversion population is built up between light and heavy hole subbands in crossed electric and magnetic fields at cryogenic temperatures. The laser has a wide gain spectrum, which allows tuning over the spectral range 50-140 cm À1 (70-200 lm or 1.5-4.2 THz) [2][3][4][5]. The laser normally generates a 20-30 cm À1 wide spectrum with up to a thousand longitudinal modes.…”

“…The laser normally generates a 20-30 cm À1 wide spectrum with up to a thousand longitudinal modes. Single mode generation [4] can be achieved using an intracavity frequency selector, which has the form of a tunable Fabry-Perot etalon coupled with the main laser cavity [2][3][4][5]. Because the selective element is placed inside the laser cavity, remarkable spectral power density is concentrated in a single longitudinal mode [4] having a width of several MHz [6].…”

“…Some effort was made to improve stability by implementing curved mirrors on the back surfaces of transparent spacers, which were similarly placed in contact with crystal end faces [7,8]. A fundamental problem with all of these closed cavity schemes is that tunability of the laser frequency is allowed only by hopping between laser modes, which are rigidly determined by the dimensions of the active crystal and other solid cavity components [5]. A typical spectral distance between longitudinal modes of the p-Ge laser is $1 GHz with a mode width of several MHz [6].…”