30 research outputs found
Angular and Temperature Tuning of Emission from Vertical-External-Cavity Surface-Emitting Lasers (VECSELs)
In this paper we demonstrate how the tuning of the VECSEL heterostructure can be precisely determined. Since the VECSEL active region is embodied in a microcavity, the photoluminescence signal collected from the chip surface is modified by the resonance of this cavity. The angle resolved photoluminescence measurements combined with the temperature tuning of the structure allowed us to precisely determine VECSEL emission features. The investigated structure consists of GaAs cavity with six InGaAs quantum wells and is designed for lasing at 980 nm. Introduction Vertical-external-cavity surface-emitting lasers (VECSELs
Calculation of atomic spontaneous emission rate in 1D finite photonic crystal with defects
We derive the expression for spontaneous emission rate in finite
one-dimensional photonic crystal with arbitrary defects using the effective
resonator model to describe electromagnetic field distributions in the
structure. We obtain explicit formulas for contributions of different types of
modes, i.e. radiation, substrate and guided modes. Formal calculations are
illustrated with a few numerical examples, which demonstrate that the
application of effective resonator model simplifies interpretation of results.Comment: Cent. Eur. J. Phys, in pres
Measurement of linewidth enhancement factor in self-assembled quantum dot semiconductor lasers emitting at 1310 nm
Measurements of the linewidth enhancement factor (also termed the aparameter)
for quantum dot semiconductor lasers emitting at 1310 nm
in both single and multiple transverse modes are presented. Values
between 1.5 and 3.0 were measured depending on the device length.
In addition, its spectral dependence within the inhomogeneously
broadened ground and excited state is investigated
Optoelectronic Devices Employing One-Dimensional Photonic Structures
This paper reviews the experimental and theoretical results obtained during work on the modern semiconductor devices employing one-dimensional photonic structures. After short review of the physical features of structures consisting of 1D stack of the alternating high and low index layers, particular attention will be given to unique features of the devices employing microcavities: resonant cavity LEDs, resonant-cavity enhanced photo-detectors, vertical cavity surface emitting lasers, and also vertical external cavity surface emitting lasers. At the end the semiconductor saturable absorber mirrors are discussed
Optoelectronic Devices Employing One-Dimensional Photonic Structures
This paper reviews the experimental and theoretical results obtained during work on the modern semiconductor devices employing one-dimensional photonic structures. After short review of the physical features of structures consisting of 1D stack of the alternating high and low index layers, particular attention will be given to unique features of the devices employing microcavities: resonant cavity LEDs, resonant-cavity enhanced photo-detectors, vertical cavity surface emitting lasers, and also vertical external cavity surface emitting lasers. At the end the semiconductor saturable absorber mirrors are discussed
Resonant Cavity Enhanced Photonic Devices
In the present paper we review our recent works on technology, basic physics, and applications of one-dimensional photonic structures. We demonstrate spontaneous emission control in InGaAs/GaAs planar microcavities with distributed Bragg reflectors. In general, observed trends are in agreement with theoretical predictions. We also demonstrate the operation of resonant-cavity light emitting diodes and optically pumped vertical cavity light emitting diodes developed recently at the Department of Physics and Technology of Low-Dimensional Structures of the Institute of Electron Technology
Ultrashort pulses supported by SESAM absorber
We have developed a mode-locked diode-pumped Yb:KYW laser generating nearly band-width limited pulses as short as 101 fs. At 1.1 W absorbed power and 3% transmission output coupler, the laser delivers 150 mW for pulse duration of 110 fs, what corresponds to an efficiency of 14%. It was achieved using semiconductor saturable absorber mirror (SESAM) grown by molecular beam epitaxy. SESAM contains a distributed Bragg reflector (DBR) completed by single quantum well (SQW) playing role of an absorbing layer. The absorbers were crystallized in accordance with the predicted structure parameters under optimised growth conditions. The resonant-like type of structures ensured relatively high enhancement factor due to antireflective properties of SiO2 capping material and a wavelength independence of a group delay dispersion. The optimisation of the growth conditions of both an absorbing layer and DBR structure were widely carried out. Optical reflectance and high resolution X-ray diffraction have been used for characterization and verification of DBR structures. It results in reduction of the nonsaturable absorption in SESAM and self-starting mode-locking of the ultrashort pulses
LT-InGaAs Layer Grown for Near Surface SESAM Application
We have developed a mode-locked diode-pumped Yb:KYW laser generating nearly band-width limited pulses as short as 101 fs using semiconductor saturable absorber mirror (SESAM). With the nonsaturable losses of 1.94% and the modulation depth of 1.48% the self-starting and stable mode-locking was observed. The nonsaturable losses are mainly related to As_{Ga}^{0}-CB transitions in InGaAs QW absorbing layer and low temperature defects. Low temperature defects are eliminated by using higher growth temperature and lower ratio of group V to group III beam equivalent pressure than typically used. The InGaAs layer was grown by molecular beam epitaxy at the temperature as high as 420°C, under the V/III ratio as low as 10. No annealing was performed