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Papers by VARTAN TER-MIKIRTYCHEV

Electronics Letters, 1995

Tunable visible solid state lasers based on frequency–doubling of Cr:forsterite and room temperat... more Tunable visible solid state lasers based on frequency–doubling of Cr:forsterite and room temperature LiF:F 2 − lasers in KTP have been developed. Extra–cavity frequency doubling produced wavelengths between 590 and 670 nm for the Cr:forsterite laser and between 555 and 595 nm for the LiF:F 2 − laser. Peak second harmonic conversion efficiencies of 7% for the Cr:forsterite laser and 7.5% for the LiF:F 2 − laser have been obtained. In each case the reduction in visible pulse energy resulting from lower fundamental pulse intensity in the wings of the tuning range has been compensated.

Springer Series in Optical Sciences, 2019

Encyclopedia of Spectroscopy and Spectrometry, 2017

Rare-earth-doped solid-state materials demonstrate extreme importance in numerous scientific and ... more Rare-earth-doped solid-state materials demonstrate extreme importance in numerous scientific and industrial applications ranging from studying fundamental properties of impurity centers in solids, solid-state material properties, up-conversion devices, scintillators, and Faraday rotators to a creation of solid-state lasers. The article presents an introduction to the optical spectroscopy of rare-earth ions in solid-state materials. We start with a description of fundamental optical processes that take place in optical centers in solids. We then describe energy-level diagrams of the rare-earth ions, non-radiative transitions, and absorption and emission properties of rare-earth ions in solids. Finally, we describe the main spectroscopic parameters of the rare-earth ions optical transitions, as well as the main energy transfer mechanisms, and review the main supporting theories.

CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference, 2009

ABSTRACT This article reported power scaling in fiber lasers and the efficiency for cladding-pump... more ABSTRACT This article reported power scaling in fiber lasers and the efficiency for cladding-pumped unidirectionally emitting Er-doped laser.

Optical Engineering, 1999

:sapphire laser are measured. The laserresonator employs a prism pair and a diaphragm creating a ... more :sapphire laser are measured. The laserresonator employs a prism pair and a diaphragm creating a ‘‘spatiallydispersive’’ cavity, and then is allowed to maintain the lasing conditionssimultaneously for different spectral components in different areas of theactive element. Second-harmonic radiation from a Q-switchedYAG:Nd

Journal of Soviet Laser Research, 1991

This paper presents the results of application to different laser installations of soft or apodiz... more This paper presents the results of application to different laser installations of soft or apodized apertures (AA) [1-3]* with smooth transmission profiles decreasing from center to edges. Two types of AA, which were made of CaF~:Pr crystals, have been used: induced absorption (IA) AM and photooxidation (PhO) AA. The-3-45-mm-diameter IA and PhO AA with smooth monotonic fiat-top profiles have been used in 1.06-#m laser amplifier systems to suppress hard-edge Fresnel diffraction rings in beam cross section and to increase the second harmonic conversion efficiency. The ~3-4-mm-diameter PhO AA with bell-like transmission profiles were placed inside the 2.94-pm and 1.06-lzm resonators of master oscillators. The tendency of the output energy to increase by 1.3-1.8 times and the decrease in beam divergence in single-mode lasing as compared with a hard-edge aperture have been observed in the experiments described below.

Excimer Lasers and Applications III, 1991

This paper presents a novel application of UV laser radiation: fabrication of soft or apodized ap... more This paper presents a novel application of UV laser radiation: fabrication of soft or apodized apertures (AA)I-3 with transmission profiles decreasing smoothly from the center to the edges for high-power single-pulse visible and near-IR lasers. Such units are used both outside and inside the cavity for beam shaping, for avoiding hard-edge Fresnel diffraction ripples in laser amplifiers, for increasing the second harmonic conversion efficiency, and for the brightness enhancement of master oscillators in single-mode lasing.

Summaries of Papers Presented at the Lasers and Electro-Optics. CLEO '02. Technical Diges

Sapphire I I ;lde /Windows Nd-YAG Laser Slab 0 Sapphire Window 0 Cooling Water Water Seal Heating... more Sapphire I I ;lde /Windows Nd-YAG Laser Slab 0 Sapphire Window 0 Cooling Water Water Seal Heating Element ... I Gasket seals (a 1 O u P 3 Fig. 1. (a) Top view of the zigzag slab, with the entrancelexit faces at Brewsters angle to the laser mode.' Each side is pumped by a ...

Optics Communications, 2002

We have developed a gain-switched room temperature single axial mode LiF:F2− laser using a couple... more We have developed a gain-switched room temperature single axial mode LiF:F2− laser using a coupled narrowband resonator. The resonator uses a classic four-prism achromatic beam expander/Littrow grating configuration, augmented with a dichroic mirror that defines a coupled resonator with: (1) reduced threshold and higher efficiency, and (2) dramatically increased axial mode separation for enhanced mode selectivity. One étalon was then

Optical and Quantum Electronics, 1999

A yellow–green solid-state laser source based on frequency- doubling of a room temperature LiF:F-... more A yellow–green solid-state laser source based on frequency- doubling of a room temperature LiF:F-2 laser in KTP is reported. Second harmonic generation of free-running and prism-tuned pulsed lasers has been characterized. Tunable operation between 555 and 595nm was obtained, with a conversion efficiency of 7.5% for the free-running laser, and up to 4% for the prism-tuned configuration. The angular bandwidth

SPIE Proceedings, 2012

ABSTRACT Spectralus presents its progress in development of miniature, highly efficient, and vers... more ABSTRACT Spectralus presents its progress in development of miniature, highly efficient, and versatile diode-pumped solid-state (DPSS) green laser source, based on a monolithic cavity microchip laser platform. The use of periodically poled MgO-doped Lithium Niobate (PPMgOLN) as the nonlinear frequency doubler together with gain material Nd3+:YVO4 allows obtaining a significant increase in the overall efficiency of the green microchip laser in comparison with other compact green laser source architectures with comparable output power. Originally, this laser source was designed to be part of the miniature and efficient RGB light source for microdisplay-based (LCOS, DLP or similar) mobile projector devices. Recently, we have extended range of operations for our original laser platform. In particular, we demonstrate the following: high peak power (>500mW), high average power (>200mW), broad temperature range of operation (-30°C - 60°C), and low noise CW operation (<0.5% RMS).

Progress in Quantum Electronics, 1996

The latest results on the development of stable roomtemperature-operative tunable color center la... more The latest results on the development of stable roomtemperature-operative tunable color center lasers and passive Qswitchers using color centers in crystals are presented. Emphasis is placed on the physics and operation conditions of highly thermally stable and photo-stable LiF and NaF color center lasers which have several unique characteristics. Attention is also paid to a high efficiency in the giant pulse generation by LiF-based passive Q-switchers. Applications of the room-temperature color center lasers to the laser spectroscopy, ultra-short pulse generation and integrated optics are also described.

physica status solidi (b), 1995

The excitation spectrum for the anti‐Stokes luminescence band with a peak at 538 nm, which arises... more The excitation spectrum for the anti‐Stokes luminescence band with a peak at 538 nm, which arises from the electronic transition of the singlet excited state 1E to the ground state 1A2 in F+3 centers of LiF crystals, is obtained for the first time using the first harmonic radiation of a tunable Al2O3:Ti3+ laser. From the quadratic dependence of the luminescence intcnsity on the average pumping power, the luminescence is understood to be caused by two‐photon excitation from the ground state 1A1 to the triplet state 3A2. The peak of the two‐photon excitation band was determined to be located at 24331 cm−1 from the 1A1 ground state.

Optics Letters, 1998

A new broadly tunable visible solid-state laser is reported. Wavelengths between 550 and 610 nm a... more A new broadly tunable visible solid-state laser is reported. Wavelengths between 550 and 610 nm are generated by intracavity frequency doubling of tuned and free-running room-temperature pulsed LiF:F 2 2 lasers in potassium titanyl phosphate. Second-harmonic energy of 1.3 mJ has been achieved, corresponding to a fundamental-to-second-harmonic conversion efficiency of 20%. Operation is optimized with respect to LiF:F 2 2 laser parameters.

Optics Communications, 1995

Efficient room-temperature color center lasers for the 1070-1310 nm region based on LiF: F; activ... more Efficient room-temperature color center lasers for the 1070-1310 nm region based on LiF: F; active elements which work with a high repetition rate and small linewidth were realized. As a result of active elements manufacturing LiF, crystals with a high F; concentration (Kl.oa4 = 0.75 cm-I) and low losses have been developed. Effective passive Q-switching of the YAG: Nd3' laser at 1064 nm has been obtained on the crystals developed.

Electronics Letters, 1995

Tunable visible solid state lasers based on frequency–doubling of Cr:forsterite and room temperat... more Tunable visible solid state lasers based on frequency–doubling of Cr:forsterite and room temperature LiF:F 2 − lasers in KTP have been developed. Extra–cavity frequency doubling produced wavelengths between 590 and 670 nm for the Cr:forsterite laser and between 555 and 595 nm for the LiF:F 2 − laser. Peak second harmonic conversion efficiencies of 7% for the Cr:forsterite laser and 7.5% for the LiF:F 2 − laser have been obtained. In each case the reduction in visible pulse energy resulting from lower fundamental pulse intensity in the wings of the tuning range has been compensated.

Springer Series in Optical Sciences, 2019

Encyclopedia of Spectroscopy and Spectrometry, 2017

Rare-earth-doped solid-state materials demonstrate extreme importance in numerous scientific and ... more Rare-earth-doped solid-state materials demonstrate extreme importance in numerous scientific and industrial applications ranging from studying fundamental properties of impurity centers in solids, solid-state material properties, up-conversion devices, scintillators, and Faraday rotators to a creation of solid-state lasers. The article presents an introduction to the optical spectroscopy of rare-earth ions in solid-state materials. We start with a description of fundamental optical processes that take place in optical centers in solids. We then describe energy-level diagrams of the rare-earth ions, non-radiative transitions, and absorption and emission properties of rare-earth ions in solids. Finally, we describe the main spectroscopic parameters of the rare-earth ions optical transitions, as well as the main energy transfer mechanisms, and review the main supporting theories.

CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference, 2009

ABSTRACT This article reported power scaling in fiber lasers and the efficiency for cladding-pump... more ABSTRACT This article reported power scaling in fiber lasers and the efficiency for cladding-pumped unidirectionally emitting Er-doped laser.

Optical Engineering, 1999

:sapphire laser are measured. The laserresonator employs a prism pair and a diaphragm creating a ... more :sapphire laser are measured. The laserresonator employs a prism pair and a diaphragm creating a ‘‘spatiallydispersive’’ cavity, and then is allowed to maintain the lasing conditionssimultaneously for different spectral components in different areas of theactive element. Second-harmonic radiation from a Q-switchedYAG:Nd

Journal of Soviet Laser Research, 1991

This paper presents the results of application to different laser installations of soft or apodiz... more This paper presents the results of application to different laser installations of soft or apodized apertures (AA) [1-3]* with smooth transmission profiles decreasing from center to edges. Two types of AA, which were made of CaF~:Pr crystals, have been used: induced absorption (IA) AM and photooxidation (PhO) AA. The-3-45-mm-diameter IA and PhO AA with smooth monotonic fiat-top profiles have been used in 1.06-#m laser amplifier systems to suppress hard-edge Fresnel diffraction rings in beam cross section and to increase the second harmonic conversion efficiency. The ~3-4-mm-diameter PhO AA with bell-like transmission profiles were placed inside the 2.94-pm and 1.06-lzm resonators of master oscillators. The tendency of the output energy to increase by 1.3-1.8 times and the decrease in beam divergence in single-mode lasing as compared with a hard-edge aperture have been observed in the experiments described below.

Excimer Lasers and Applications III, 1991

This paper presents a novel application of UV laser radiation: fabrication of soft or apodized ap... more This paper presents a novel application of UV laser radiation: fabrication of soft or apodized apertures (AA)I-3 with transmission profiles decreasing smoothly from the center to the edges for high-power single-pulse visible and near-IR lasers. Such units are used both outside and inside the cavity for beam shaping, for avoiding hard-edge Fresnel diffraction ripples in laser amplifiers, for increasing the second harmonic conversion efficiency, and for the brightness enhancement of master oscillators in single-mode lasing.

Summaries of Papers Presented at the Lasers and Electro-Optics. CLEO '02. Technical Diges

Sapphire I I ;lde /Windows Nd-YAG Laser Slab 0 Sapphire Window 0 Cooling Water Water Seal Heating... more Sapphire I I ;lde /Windows Nd-YAG Laser Slab 0 Sapphire Window 0 Cooling Water Water Seal Heating Element ... I Gasket seals (a 1 O u P 3 Fig. 1. (a) Top view of the zigzag slab, with the entrancelexit faces at Brewsters angle to the laser mode.' Each side is pumped by a ...

Optics Communications, 2002

We have developed a gain-switched room temperature single axial mode LiF:F2− laser using a couple... more We have developed a gain-switched room temperature single axial mode LiF:F2− laser using a coupled narrowband resonator. The resonator uses a classic four-prism achromatic beam expander/Littrow grating configuration, augmented with a dichroic mirror that defines a coupled resonator with: (1) reduced threshold and higher efficiency, and (2) dramatically increased axial mode separation for enhanced mode selectivity. One étalon was then

Optical and Quantum Electronics, 1999

A yellow–green solid-state laser source based on frequency- doubling of a room temperature LiF:F-... more A yellow–green solid-state laser source based on frequency- doubling of a room temperature LiF:F-2 laser in KTP is reported. Second harmonic generation of free-running and prism-tuned pulsed lasers has been characterized. Tunable operation between 555 and 595nm was obtained, with a conversion efficiency of 7.5% for the free-running laser, and up to 4% for the prism-tuned configuration. The angular bandwidth

SPIE Proceedings, 2012

ABSTRACT Spectralus presents its progress in development of miniature, highly efficient, and vers... more ABSTRACT Spectralus presents its progress in development of miniature, highly efficient, and versatile diode-pumped solid-state (DPSS) green laser source, based on a monolithic cavity microchip laser platform. The use of periodically poled MgO-doped Lithium Niobate (PPMgOLN) as the nonlinear frequency doubler together with gain material Nd3+:YVO4 allows obtaining a significant increase in the overall efficiency of the green microchip laser in comparison with other compact green laser source architectures with comparable output power. Originally, this laser source was designed to be part of the miniature and efficient RGB light source for microdisplay-based (LCOS, DLP or similar) mobile projector devices. Recently, we have extended range of operations for our original laser platform. In particular, we demonstrate the following: high peak power (>500mW), high average power (>200mW), broad temperature range of operation (-30°C - 60°C), and low noise CW operation (<0.5% RMS).

Progress in Quantum Electronics, 1996

The latest results on the development of stable roomtemperature-operative tunable color center la... more The latest results on the development of stable roomtemperature-operative tunable color center lasers and passive Qswitchers using color centers in crystals are presented. Emphasis is placed on the physics and operation conditions of highly thermally stable and photo-stable LiF and NaF color center lasers which have several unique characteristics. Attention is also paid to a high efficiency in the giant pulse generation by LiF-based passive Q-switchers. Applications of the room-temperature color center lasers to the laser spectroscopy, ultra-short pulse generation and integrated optics are also described.

physica status solidi (b), 1995

The excitation spectrum for the anti‐Stokes luminescence band with a peak at 538 nm, which arises... more The excitation spectrum for the anti‐Stokes luminescence band with a peak at 538 nm, which arises from the electronic transition of the singlet excited state 1E to the ground state 1A2 in F+3 centers of LiF crystals, is obtained for the first time using the first harmonic radiation of a tunable Al2O3:Ti3+ laser. From the quadratic dependence of the luminescence intcnsity on the average pumping power, the luminescence is understood to be caused by two‐photon excitation from the ground state 1A1 to the triplet state 3A2. The peak of the two‐photon excitation band was determined to be located at 24331 cm−1 from the 1A1 ground state.

Optics Letters, 1998

A new broadly tunable visible solid-state laser is reported. Wavelengths between 550 and 610 nm a... more A new broadly tunable visible solid-state laser is reported. Wavelengths between 550 and 610 nm are generated by intracavity frequency doubling of tuned and free-running room-temperature pulsed LiF:F 2 2 lasers in potassium titanyl phosphate. Second-harmonic energy of 1.3 mJ has been achieved, corresponding to a fundamental-to-second-harmonic conversion efficiency of 20%. Operation is optimized with respect to LiF:F 2 2 laser parameters.

Optics Communications, 1995

Efficient room-temperature color center lasers for the 1070-1310 nm region based on LiF: F; activ... more Efficient room-temperature color center lasers for the 1070-1310 nm region based on LiF: F; active elements which work with a high repetition rate and small linewidth were realized. As a result of active elements manufacturing LiF, crystals with a high F; concentration (Kl.oa4 = 0.75 cm-I) and low losses have been developed. Effective passive Q-switching of the YAG: Nd3' laser at 1064 nm has been obtained on the crystals developed.