We demonstrate efficient wavelength tuning by means of hydrostatic pressure of an InGaN/GaN laser diode grown on bulk GaN crystal. Energy shifts of the emitted light with pressure have been found to be about 36 meV/GPa, which are high magnitudes for nitride-based device structures. This result is interpreted as being indicative of efficient screening of built-in electric fields in the studied device. Furthermore, the threshold current of the laser diode was found to be independent of applied pressure. The high magnitude of the pressure coefficient allowed for the achievement of a laser tuning range of up to 10 nm in the blue/violet region, using compact pressure equipment.

In Ga As Sb ∕ Al Ga As Sb type-I midinfrared diode lasers emitting continuous wave at 2.4μm at room temperature have been studied under high hydrostatic pressure. When the pressure was increased up to 19kbar, the threshold current varied from 240to400A∕cm2, showing a minimum of 200A∕cm2 close to 8kbar, and the emission spectra shifted to shorter wavelengths by up to 700nm (i.e., from 2.4μmto1.7μm). This exceptional tuning range could be very useful in tunable diode laser absorption spectroscopy.

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Photocurrent spectroscopy and hydrostatic-pressure-dependent electroluminescence are used to show that heavy 1×1019cm−3 Si doping of quantum barriers is sufficient to achieve full screening of polarization-induced electric fields (PIEFs) in nitride light emitting diodes (LEDs) and laser diodes (LDs) with InGaN quantum wells. Furthermore, it is shown that at currents close to lasing threshold in nitride LDs injected charge alone is sufficient to achieve full screening of PIEFs. In contrast, full screening at low currents can only be accomplished via Si doping of quantum barriers.

The emission wavelength of broad-area AlGaInP/InGaP quantum-well lasers is tuned by the application of high hydrostatic pressure and low temperature from 645 down to 575 nm, i.e., from the red through the orange to yellow spectral range. Emission powers up to 300 mW are obtained in the full tuning range. The pressure and temperature dependence of threshold currents indicates that leakage occurs into the L and X minima in the barriers.

Pressure and temperature change the bandgap of III -V semiconductors and therefore they shift the gain spectrum of laser diodes. With 20 kbar pressure (achievable in a liquid pressure cell) we can increase the energy of the laser emission by about 200 meV for lasers grown on GaAs, InP, or GaSb. The main physical limitation of pressure tuning for shorter wavelengths (i.e. between 600 and 800 nm) is the reduction of indirect gap (Γ -X) in the barriers and claddings of the laser structure, leading to strong increase of leakage and threshold currents. In this wavelength range temperature tuning seems more practical. Cooling down the laser from room temperature (300 K) to about 100 K we should be able to increase the emission energy by about 80 meV. The combination of pressure/temperature tuning with tuning by external grating turned out to combine the merits of both methods: wide spectral range, narrow linewidth, stable emission wavelength. The method seems promising although several issues still have to be addressed like the reliability of lasers and pressure cells after multiple pressure cycles, stability of coupling between the laser diode and fiber under high pressure etc.

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The main objective of this work was to combine the positive characteristics of transparent photopolymers and light-sensitive chalcogenide glasses, with aim to improve the amplitude-phase modulation characteristics of in situ optically recorded photonic elements on the surface, and in the bulk of thick composite layer on a given substrate. The positive results were obtained due to the developed technology routes of nanocomposite (NC) fabrication by intermixing selected, optically tunable, VIS-NIR transparent and high refractive index As-S (Se) nanoparticles (NPs) produced by chemical dissolution, and acrylate monomers with initiators. Subsequent photopolymerization of such nanocomposite occurs during optical recording photonic elements and is supplemented by mass-transport processes, which enhance relief parameters. Structure, optical parameters of the new light-sensitive media and conditions of one step recording of optical elements in it were investigated.