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The possibility of using vertical-emitting lasers with intracavity contacts (IC-VCSEL) and a rhomboidal oxide current aperture for creating a non-zero magnetic field optically pumped atomic magnetometers (OPM) with a 133Cs vapor cell for magnetoencephalographic (MEG) systems were demonstrated. Relative intensity noise (RIN) and polarization resolved RIN of the IC-VCSEL in the 895 nm range with different mirror losses (linewidth) in the frequency range from 1 Hz to 100 kHz were experimentally investigated. Lasers with low mirror loss (narrow linewidth) have polarization resolved RIN comparable to amplitude noise. For IC-VCSEL with an output optical power of 0.8 mW and a linewidth of 55 MHz, the noise level measured is 148 dB/Hz in 1 Hz bandwidth at 40 kHz frequency. The ultimate sensitivity of OPM based on two-beam MZ-scheme with studied VCSELs was estimated as ~ 11 fT/sqrt(Hz)sqrt. Keywords: vertical-cavity surface-emitting laser (VCSEL), magnetoencephalographic (MEG) systems, optically pumped atomic magnetometers (OPAM), relative intensity noise (RIN), polarization-resolved RIN.

The impact of transverse optical confinement on the static and spectral characteristics of 1.55 μm vertical-cavity surface-emitting lasers (WF-VCSEL) with a buried tunnel junction (BTJ) n++-InGaAs/p++-InGaAs/p++-InAlGaAs, implemented using molecular-beam epitaxy and wafer fusion. It was found that for VCSELs with a tunnel junction (TJ) etching depth of 15 nm, the single-mode lasing occurs up to 8 μm BTJ mesa size due to a relatively weak lateral optical confinement, while the effect of a saturable absorber (SA) appears when the BTJ mesa size is less than 7 μm. Enhancing lateral optical confinement by increasing the BTJ etching depth up to 20 nm leads to suppression of the SA effect at the BTJ mesa size of 5-6 μm, but simultaneously limits the maximum single-mode optical power. According to obtained results an increase in the spectral mismatch between the maximum of the gain spectrum of the active region and the resonance wavelength of the WF-VCSEL up to ~ 35-50 nm will make it possible to suppress the undesirable SA effect in a wide range of the BTJ mesa sizes maintaining the single-mode lasing. Keywords: vertical-cavity surface-emitting laser, wafer fusion, molecular beam epitaxy, single-mode operation, saturable absorber.

The analysis of internal optical loss and internal quantum efficiency in 1.3 μm-range InAlGaAsP/AlGaAs a composite n+-InGaAs/p+-InGaAs/p+-InAlGaAs tunnel junction obtained in the frame of molecular-beam epitaxy and wafer fusion technology. The level of internal optical losses in the lasers under study was varied by depositing a dielectric layer on the surface of the output mirror. It is shown that it is possible in principle to achieve low internal optical loss of less than 0.08% and 0.14% per one pass (round-trip) at temperatures of 20oC and 90oC, respectively. Keywords: vertical-cavity surface-emitting laser, wafer fusion, tunnel junction, superlattice, internal optical loss.

The possibility of fabrication of 4.6 μm spectral range quantum-cascade laser heterostructures by molecular-beam epitaxy technique with non-selective overgrowth by the metalorganic vapour-phase epitaxy is shown. The active region of the laser was formed on the basis of a heteropair of In0.67Ga0.33As/In0.36Al0.64As solid alloys. The waveguide claddings are formed by indium phosphide. The results of surface defects inspection and X-ray diffraction analysis of quantum-cascade laser heterostructures allow to conclude that the structural quality of the heterostructures is high and the estimated value of the root mean square surface roughness does not exceed 0.7 nm. Lasers with four cleaved facets exhibit lasing at room temperature with a relatively low threshold current density of the order of 1 kA/cm2. Keywords: superlattices, quantum-cascade laser, epitaxy, indium phosphide.