Ruby laser

About: Ruby laser is a research topic. Over the lifetime, 2474 publications have been published within this topic receiving 38933 citations. The topic is also known as: corundum laser & ruby rod.

Effect of pulsed laser action on hole-energy spectrum of Ge/Si self-assembled quantum dots

Abstract: Space-charge spectroscopy has been used to study the hole energy spectrum of an array of Ge quantum dots (QD's) coherently embedded in a Si matrix and subjected to a ruby laser $(\ensuremath{\lambda}=694\phantom{\rule{0.3em}{0ex}}\mathrm{nm})$ nanosecond irradiation ex situ. The laser energy density in a single pulse was near the melting threshold of the Si surface. The number of laser pulses was varied from 1 to 10, and the duration of each pulse was $80\phantom{\rule{0.3em}{0ex}}\mathrm{ns}$. From the capacitance-voltage characteristics, temperature- and frequency-dependent admittance measurements, the energies of holes confined in Ge QD's were determined. The pulsed laser annealing was found to result in a deepening of the hole energy level relative to the bulk Si valence band edge and in a decrease of the hole energy dispersion. After the treatment with ten laser pulses, the spread of the hole energies due to varying sizes of the QD's within the ensemble was reduced by a factor of about 2. The obtained results give evidence for a substantial reduction of the QD's size dispersion and for a narrowing distribution of the hole energy levels stimulated by nanosecond laser irradiation. A possible explanation of the improved uniformity of QD's sizes involves dissolving small size Ge QD's in a Si matrix by pulsed laser melting of the Ge nanoclusters and their subsequent intermixing with surrounding solid Si.

Formation of ohmic contacts to III–V semiconductors, using a laser beam

Abstract: This paper reports on the use of a focused laser beam to form ohmic contacts on the surfaces of III–V semiconductors. We have produced “ohmic” contacts on several III–V compounds (GaP, GaAs, GaSb, InAs and InSb) using a pulsed ruby laser (λ = 0·6943 μm), a pulsed YAG laser (λ = 1·06 μm) and a burst of pulses from a Q-switched CO2 (λ = 10·6 μm) laser. The initial results show that only those lasers whose wavelengths fall within the absorption band of the semiconductor (free carrier absorption or band to band transition region) can be successfully used for this purpose. Contacts produced in this manner show ohmic characteristics similar to that obtained with conventional techniques. The method does not require any special surface preparation, and since the heating is limited to a localized surface region it has no effect on the junction properties of a device.

Dielectric Mirror Damage by Laser Radiation over a Range of Pulse Durations and Beam Radii.

Abstract: Laser induced damage characteristics have been studied for twelve, multiple-layer dielectric, 95% reflecting mirrors irradiated with single ruby laser pulses of 20-nsec and 20-psec duration and Gaussian beam radii ranging from 0.06 mm to 0.24 mm. During measurements to determine damage threshold the pulse energy, an oscilloscope trace of the pulse, and the beam’s transverse energy density profile at the surface being damaged are recorded for each shot. In a separate set of experiments, the temporal development of coating breakup and plasma formation is investigated. The experimental results are discussed in the context of possible damage mechanisms.