A. M. Monakhov

Physical working principles of semiconductor disk lasers

The physical working principles of whispering gallery mode semiconductor disk lasers are examined. A new method is proposed for measuring the single-pass gain. The theory of cylindrical waveguides is considered. The spectral characteristics of whispering gallery mode lasers is investigated experimentally in the temperature range 4-300 K. It is shown that lasers of this kind are very promising as potential laser radiation sources operating at room temperature.

Infrared whispering-gallery-mode lasers (λ= 2.4 μm) with convex disk cavity operating at room temperature

A whispering gallery mode (WGM) semiconductor laser with a convex disk cavity operating at room temperature in the middle-IR range (λ = 2.4 μm) has been created for the first time. The convex cavity was formed by etching in a specially selected CrO3-HF-H2O mixture. The room-temperature emission spectra have been measured. The laser generates WGMs at room temperature in a pulsed regime.

Semiconductor WGM lasers for the mid-IR spectral range

Disk-cavity whispering-gallery-mode (WGM) semiconductor lasers for the mid-IR spectral range have been developed. The specific properties of these devices are investigated.

Interference of emission from disk-shaped lasers based on quantum-confined AlGaAsSb/InGaAsSb nanoheterostructures

Directivity patterns of disk-shaped whispering gallery mode (WGM) semiconductor lasers based on quantum-confined AlGaAsSb/InGaAsSb nanoheterostructures have been studied. The cavities of disk lasers were manufactured by wet chemical etching and had the shape of a truncated cone with a height of 15 μm. The top (about 5-μm-high) part of the cavity had a cylindrical shape. A flat ring with a width equal to the thickness of the active region was protruding ∼1 μm out of the side face of the cavity. The directivity diagram of the disc WGM laser exhibits a ring-shaped interference pattern with several maxima separated by an angle of ∼6°. The interference pattern observed in both spontaneous and laser generation regimes can be explained by the interference of rays emitted directly from the ring and those reflected from the etched surface of the crystal.

Frequency-tuned semiconductor whispering-gallery-mode laser (λ = 2.35 µm) operating at room temperature

Frequency tuning in a whispering gallery mode (WGM) semiconductor laser (λ = 2.35 µm) with a sector (half-disk) cavity has been studied. Pumping by current pulses with a duration of up to 1.2 µs is accompanied by smooth tuning of the main WGM toward longer wavelengths by 30 Å at room temperature, which is 1.4 times the intermode distance.

Continuous-wave disk WGM lasers (λ = 3.0 μm) based on InAs/InAsSbP heterostructures

IR semiconductor WGM lasers operating in the continuous-wave (CW) mode at a wavelength of 3.04 μm have been fabricated by metal-organic vapor-phase epitaxy on the basis of InAs/InAsSbP heterostructures. Their emission spectra were studied in the temperature range from 77 to 125 K. The lasers operating in the CW mode have a threshold current of 25 mA at a temperature of 77 K. The WGM lasers also work in the pulsed mode up to 125 K. The dynamic range of operation for the disk lasers is substantially extended to currents exceeding the threshold current by a factor of 200.

On the experimental data processing of magnetoresistance oscillations in two-dimensional electron gas

A new method for processing data on the Shubnikov-de Haas effect in quasi-two-dimensional systems is suggested.

Characterization of quantum-confinement whispering-gallery-mode lasers operating above room temperature

The temperature dependence of the threshold current density and emission spectra of disk-shaped quantum-confinement lasers operating on whispering-gallery modes has been studied in the 23–180°C interval. As the temperature is increased in this interval, the radiation wavelengths grows from 2.24 to 2.42 μm, stable lasing is observed up to 177°C, and the threshold current exhibits exponential growth in proportion to exp(T/T0) with T0 = 70 K.

Mid-infrared radiation sources based on coupled disk cavities

IR radiation sources representing optically coupled semiconductor disk lasers with active regions based on quantum-confined GaInAsSb/AlGaAsSb heterostructures have been created. It is shown that this system ensures single-mode generation in optically coupled cavities operating on whispering gallery modes (WGMs). Conditions for WGM lasing are determined as dependent on the distance between two optically coupled disk cavities.

Visual observation of frequency tuning in whispering gallery mode diode laser at room temperature

We report on the direct observation of an increase in the wavelength of output radiation during the pumping current pulse in a whispering gallery mode (WGM) semiconductor diode laser (2.35 μm) with a sector (half-disk) cavity. During the current pulse with a duration of up to 1.5 μs, the main WGM wavelength smoothly increases by 30 Å at room temperature.