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Peter J Pauzauskie - One of the best experts on this subject based on the ideXlab platform.

  • quantum point defects for Solid State Laser refrigeration
    Advanced Materials, 2021
    Co-Authors: Xiaojing Xia, Anupum Pant, Abbie S Ganas, Fedor Jelezko, Peter J Pauzauskie
    Abstract:

    Herein, the role that point defects have played over the last two decades in realizing Solid-State Laser refrigeration is discussed. A brief introduction to the field of Solid-State Laser refrigeration is given with an emphasis on the fundamental physical phenomena and quantized electronic transitions that have made Solid-State Laser-cooling possible. Lanthanide-based point defects, such as trivalent ytterbium ions (Yb3+ ), have played a central role in the first demonstrations and subsequent development of advanced materials for Solid-State Laser refrigeration. Significant discussion is devoted to the quantum mechanical description of optical transitions in lanthanide ions, and their influence on Laser cooling. Transition-metal point defects have been shown to generate substantial background absorption in ceramic materials, decreasing the overall efficiency of a particular Laser refrigeration material. Other potential color centers based on fluoride vacancies with multiple potential charge States are also considered. In conclusion, novel materials for Solid-State Laser refrigeration, including color centers in diamond that have recently been proposed to realize the Solid-State Laser refrigeration of semiconducting materials, are discussed.

  • Solid State Laser refrigeration of a composite semiconductor yb ylif 4 optomechanical resonator
    Nature Communications, 2020
    Co-Authors: Anupum Pant, Xiaojing Xia, Peter J Pauzauskie, James E Davis
    Abstract:

    Photothermal heating represents a major constraint that limits the performance of many nanoscale optoelectronic and optomechanical devices including nanoLasers, quantum optomechanical resonators, and integrated photonic circuits. Here, we demonstrate the direct Laser refrigeration of a semiconductor optomechanical resonator >20 K below room temperature based on the emission of upconverted, anti-Stokes photoluminescence of trivalent ytterbium ions doped within a yttrium-lithium-fluoride (YLF) host crystal. Optically-refrigerating the lattice of a dielectric resonator has the potential to impact several fields including scanning probe microscopy, the sensing of weak forces, the measurement of atomic masses, and the development of radiation-balanced Solid-State Lasers. In addition, optically refrigerated resonators may be used in the future as a promising starting point to perform motional cooling for exploration of quantum effects at mesoscopic length scales, temperature control within integrated photonic devices, and Solid-State Laser refrigeration of quantum materials. Optically refrigerated resonators may be useful in optical devices and exploring quantum effects. Here, the authors show Laser refrigeration of a semiconductor mechanical oscillator Yb:YLF host crystal and lowering the thermal load temperature.

  • hydrothermal synthesis and Solid State Laser refrigeration of ytterbium doped potassium lutetium fluoride klf microcrystals
    ChemRxiv, 2020
    Co-Authors: Xiaojing Xia, Anupum Pant, Peter J Pauzauskie, Xuezhe Zhou, E A Dobretsova, Alex Bard, Matthew B Lim, Joo Yeon Roh, Daniel R Gamelin
    Abstract:

    Fluoride crystals, due to their low phonon energies, are attractive hosts of trivalent lanthanide ions for applications in upconverting phosphors, quantum information science, and Solid-State Laser refrigeration. In this article, we report the rapid, low-cost hydrothermal synthesis of potassium lutetium fluoride (KLF) microcrystals for applications in Solid-State Laser refrigeration. Four crystalline phases were synthesized, namely orthorhombic K2LuF5 (Pnma), trigonal KLuF4 (P3121), orthorhombic KLu2F7 (Pna21), and cubic KLu3F10 (Fm3m), with each phase exhibiting unique microcrystalline morphologies. Luminescence spectra and emission lifetimes of the four crystalline phases were characterized based on the point-group symmetry of trivalent cations. Laser refrigeration was measured by observing both the optomechanical eigenfrequencies of microcrystals on cantilevers in vacuum, and also the Brownian dynamics of optically trapped microcrystals in water. Among all four crystalline phases, the most significant cooling was observed for 10%Yb:KLuF4 with cooling of 8.6 $\pm$ 2.1 K below room temperature. Reduced heating was observed with 10%Yb:K2LuF5

Kenju Otsuka - One of the best experts on this subject based on the ideXlab platform.

  • easy measurement and analysis method of zeta potential and electrophoretic mobility of water dispersed colloidal particles by using a self mixing Solid State Laser
    Journal of Applied Physics, 2013
    Co-Authors: S. Sudo, T Ohtomo, Kenju Otsuka
    Abstract:

    We describe a highly sensitive method of measuring electrophoretic mobility and zeta potential of water-dispersed colloidal particles by using a self-mixing Laser Doppler velocimeter with a Laser-diode-pumped, thin-slice Solid-State Laser with extremely high optical sensitivity. The power spectra of Laser output modulated by reinjected Laser light scattered by the electrophoretic particles were observed. The power spectrum cannot be described by the well-known formula for translational motion or flowing Brownian motion, i.e., a combination of Doppler shift, diffusion, and translation. The power spectra shape is found to reflect the velocity distribution of electrophoretic particles in a capillary tube due to the electro-osmotic flow contribution. Not only evaluation of the electrophoretic mobility and zeta potential but also the particle diameter undergoing electrophoretic motion can be performed from the shape of the power spectrum.

  • generation of vortex array beams from a thin slice Solid State Laser with shaped wide aperture Laser diode pumping
    Optics Letters, 2009
    Co-Authors: Kenju Otsuka, Shu Chun Chu
    Abstract:

    We demonstrate vortex array-beam generations from a thin-slice, wide-aperture, Solid-State Laser with Laser-diode end-pumping. Radial and rectangular vortex arrays were found to be formed in a controlled fashion with symmetric and asymmetric pump-beam profiles, respectively. Most of these vortices exhibited single-frequency oscillations arising from a spontaneous process of transverse mode locking of degenerate or nearly degenerate modes assisted by the Laser nonlinearity. Single-frequency rectangular array beams consisting of a large number of vortices, e.g., closely packed 25, 36, or 46 vortex pixels, were generated, originating from Ince–Gaussian modes excited by the asymmetric pumping.

  • real time nanometer vibration measurement with a self mixing microchip Solid State Laser
    Optics Letters, 2002
    Co-Authors: Kenju Otsuka, Jingyuan Ko
    Abstract:

    Nanometer vibration analysis of a target has been demonstrated by a self-aligned optical feedback vibrometry technique that uses a Laser-diode-pumped microchip Solid-State Laser. The Laser output waveform, which was modulated through interference between a lasing field and an extremely weak <-100‐dB frequency-modulated (FM) feedback field, was analyzed by the Hilbert transformation to yield the vibration waveform of the target. Experimental signal characteristics have been reproduced by numerical simulations. Real-time vibration measurement has also been achieved with a simple FM demodulation circuit.

  • ultrahigh sensitivity Laser doppler velocimetry with a microchip Solid State Laser
    Applied Optics, 1994
    Co-Authors: Kenju Otsuka
    Abstract:

    Highly sensitive Laser Doppler velocimetry featuring the simultaneous measurement of light-scattering objects moving at different velocities and vibration sensing based on Doppler-shifted light-injectioninduced intensity modulation in an externally pumped microchip Solid-State Laser is demonstrated.

Thomas Sudmeyer - One of the best experts on this subject based on the ideXlab platform.

  • full stabilization and characterization of an optical frequency comb from a diode pumped Solid State Laser with ghz repetition rate
    Optics Express, 2017
    Co-Authors: Sargis Hakobyan, Stéphane Schilt, U Keller, Aline S Mayer, Valentin J Wittwer, Pierre Brochard, Kutan Gurel, Thomas Sudmeyer
    Abstract:

    We demonstrate the first self-referenced full stabilization of a diode-pumped Solid-State Laser (DPSSL) frequency comb with a GHz repetition rate. The Yb:CALGO DPSSL delivers an average output power of up to 2.1 W with a typical pulse duration of 96 fs and a center wavelength of 1055 nm. A carrier-envelope offset (CEO) beat with a signal-to-noise ratio of 40 dB (in 10-kHz resolution bandwidth) is detected after supercontinuum generation and f-to-2f interferometry directly from the output of the oscillator, without any external amplification or pulse compression. The repetition rate is stabilized to a reference synthesizer with a residual integrated timing jitter of 249 fs [10 Hz - 1 MHz] and a relative frequency stability of 10-12/s. The CEO frequency is phase-locked to an external reference via pump current feedback using home-built modulation electronics. It achieves a loop bandwidth of ~150 kHz, which results in a tight CEO lock with a residual integrated phase noise of 680 mrad [1 Hz - 1 MHz]. We present a detailed characterization of the GHz frequency comb that combines a noise analysis of the repetition rate frep, of the CEO frequency fCEO, and of an optical comb line at 1030 nm obtained from a virtual beat with a narrow-linewidth Laser at 1557 nm using a transfer oscillator. An optical comb linewidth of about 800 kHz is assessed at 1-s observation time, for which the dominant noise sources of frep and fCEO are identified.

  • gigahertz frequency comb from a diode pumped Solid State Laser
    Optics Express, 2014
    Co-Authors: Alexander Klenner, Stéphane Schilt, Thomas Sudmeyer
    Abstract:

    We present the first stabilization of the frequency comb offset from a diode-pumped gigahertz Solid-State Laser oscillator. No additional external amplification and/or compression of the output pulses is required. The Laser is reliably modelocked using a SESAM and is based on a diode-pumped Yb:CALGO gain crystal. It generates 1.7-W average output power and pulse durations as short as 64 fs at a pulse repetition rate of 1 GHz. We generate an octave-spanning supercontinuum in a highly nonlinear fiber and use the standard f-to-2f carrier-envelope offset (CEO) frequency fCEO detection method. As a pump source, we use a reliable and cost-efficient commercial diode Laser. Its multi-spatial-mode beam profile leads to a relatively broad frequency comb offset beat signal, which nevertheless can be phase-locked by feedback to its current. Using improved electronics, we reached a feedback-loop-bandwidth of up to 300 kHz. A combination of digital and analog electronics is used to achieve a tight phase-lock of fCEO to an external microwave reference with a low in-loop residual integrated phase-noise of 744 mrad in an integration bandwidth of [1 Hz, 5 MHz]. An analysis of the Laser noise and response functions is presented which gives detailed insights into the CEO stabilization of this frequency comb.

  • femtosecond diode pumped Solid State Laser with a repetition rate of 4 8 ghz
    Optics Express, 2012
    Co-Authors: S Pekarek, Thomas Sudmeyer, Alexander Klenner, Christian Fiebig, K Paschke, G Erbert
    Abstract:

    We report on a diode-pumped Yb:KGW (ytterbium-doped potassium gadolinium tungState) Laser with a repetition rate of 4.8 GHz and a pulse duration of 396 fs. Stable fundamental modelocking is achieved with a semiconductor saturable absorber mirror (SESAM). The average output power of this compact diode-pumped Solid State Laser is 1.9 W which corresponds to a peak power of 0.9 kW and the optical-to-optical efficiency is 36%. To the best of our knowledge, this is the femtosecond DPSSL with the highest repetition rate ever reported so far.

  • Noise properties of an optical frequency comb from a SESAM-mode-locked 1.5-μm Solid-State Laser stabilized to the 10-13level
    Applied Physics B: Lasers and Optics, 2012
    Co-Authors: Stéphane Schilt, Nikola Bucalovic, Gianni Di Domenico, Max C. Stumpf, Christian Schori, Vladimir Dolgovskiy, Selina Pekarek, Thomas Sudmeyer, Andreas E. H. Oehler, Ulrich Keller
    Abstract:

    We present a detailed investigation of the noise properties of an optical frequency comb generated from a femtosecond diode-pumped Solid-State Laser operating in the 1.5-μm spectral region. The stabilization of the passively mode-locked Er:Yb:glass Laser oscillator, referred to as ERGO, is achieved using pump power modulation for the control of the carrier envelope offset (CEO) frequency and by adjusting the Laser cavity length for the control of the repetition rate. The stability and the noise of the ERGO comb are characterized in free-running and in phase-locked operation by measuring the noise properties of the CEO, of the repetition rate, and of a comb line at 1558 nm. The comb line is analyzed from the heterodyne beat signal with a cavity-stabilized ultra-narrow-linewidth Laser using a frequency discriminator. Two different schemes to stabilize the comb to a radio-frequency (RF) reference are compared. The comb properties (phase noise, frequency stability) are limited in both cases by the RF oscillator used to stabilize the repetition rate, while the contribution of the CEO is negligible at all Fourier frequencies, as a consequence of the low-noise characteristics of the CEO-beat. A linewidth of ≈150 kHz and a fractional frequency instability of 4.2×10−13 at 1 s are obtained for an optical comb line at 1558 nm. Improved performance is obtained by stabilizing the comb to an optical reference, which is a cavity-stabilized ultra-narrow linewidth Laser at 1558 nm. The fractional frequency stability of 8×10−14 at 1 s, measured in preliminary experiments, is limited by the reference oscillator used in the frequency comparison.

  • fully stabilized optical frequency comb with sub radian ceo phase noise from a sesam modelocked 1 5 µm Solid State Laser
    Optics Express, 2011
    Co-Authors: Stéphane Schilt, Nikola Bucalovic, Gianni Di Domenico, Christian Schori, Vladimir Dolgovskiy, S Pekarek, M C Stumpf, A E H Oehler, Thomas Sudmeyer
    Abstract:

    We report the first full stabilization of an optical frequency comb generated from a femtosecond diode-pumped Solid-State Laser (DPSSL) operating in the 1.5-μm spectral region. The stability of the comb is characterized in free-running and in phase-locked operation by measuring the noise properties of the carrier-envelope offset (CEO) beat, of the repetition rate, and of a comb line at 1558 nm. The high Q-factor of the semiconductor saturable absorber mirror (SESAM)-modelocked 1.5-µm DPSSL results in a low-noise CEO-beat, for which a tight phase lock can be much more easily realized than for a fiber comb. Using a moderate feedback bandwidth of only 5.5 kHz, we achieved a residual integrated phase noise of 0.72 rad rms for the locked CEO, which is one of the smallest values reported for a frequency comb system operating in this spectral region. The fractional frequency stability of the CEO-beat is 20‑fold better than measured in a standard self-referenced commercial fiber comb system and contributes only 10−15 to the optical carrier frequency instability at 1 s averaging time.

Patrick Georges - One of the best experts on this subject based on the ideXlab platform.

  • Passively Q-switched diode-pumped Er:YAG Solid-State Laser
    Optics Letters, 2013
    Co-Authors: Adrien Aubourg, Julien Didierjean, Nicolas Aubry, François Balembois, Patrick Georges
    Abstract:

    We demonstrated Laser operation of a passively Q-switched diode-pumped Er:YAG Solid-State Laser emitting at 1645 or 1617 nm depending on the initial transmission of the Cr:ZnSe saturable absorber. The crystal emitted up to 10 W at 1645 nm and up to 8 W at 1617 nm in CW mode while pumped with 65 W of incident pump power at 1533 nm. In passive Q-switched mode with 40 W of incident power, a Cr:ZnSe saturable absorber with initial transmission of 85% led to 330 μJ pulse energy, 61 ns pulse duration at a repetition rate of 1460 Hz at 1645 nm. An 80% initial transmission Cr:ZnSe sample led to 510 μJ energy pulses, 41 ns pulse duration at a repetition rate of 820 Hz with a central wavelength change from 1645 to 1617 nm. This is the first reported passively Q-switched diode-pumped Er:YAG Laser operating on the I13/24→I15/24 transition.

Ioannis G Pallikaris - One of the best experts on this subject based on the ideXlab platform.

  • Case Report Transepithelial Phototherapeutic Keratectomy Using a 213-nm Solid-State Laser System Followed by Corneal Collagen Cross-Linking with Riboflavin and UVA Irradiation
    2020
    Co-Authors: George D Kymionis, Michael A Grentzelos, Alexandra E Karavitaki, George A Kounis, Georgios A Kontadakis, Sonia Yoo, Ioannis G Pallikaris
    Abstract:

    properly cited. Purpose. To present a case of a keratoconic patient who underwent epithelial removal with transepithelial phototherapeutic keratectomy (t-PTK) using a 213-nm Solid-State Laser system followed by corneal collagen cross-linking (CXL) with riboflavin and ultraviolet-A (UVA) irradiation. Methods. Case report. Results. A twenty-four-year-old male with keratoconus underwent CXL treatment after epithelial removal with t-PTK using a Solid-State Laser system. No intra-or early postoperative complications were found. One month postoperatively, uncorrected visual acuity (UCVA) improved from 20/63 to 20/32 while best spectaclecorrected visual acuity (BSCVA) improved from 20/40 to 20/25. Corneal topography revealed a significant improvement which remained stable during the six-month followup period. Conclusions. Epithelial removal with t-PTK before CXL could improve patient's visual outcome

  • transepithelial phototherapeutic keratectomy using a 213 nm Solid State Laser system followed by corneal collagen cross linking with riboflavin and uva irradiation
    Journal of Ophthalmology, 2010
    Co-Authors: George D Kymionis, Michael A Grentzelos, Alexandra E Karavitaki, George A Kounis, Georgios A Kontadakis, Ioannis G Pallikaris
    Abstract:

    Purpose. To present a case of a keratoconic patient who underwent epithelial removal with transepithelial phototherapeutic keratectomy (t-PTK) using a 213-nm Solid-State Laser system followed by corneal collagen cross-linking (CXL) with riboflavin and ultraviolet-A (UVA) irradiation. Methods. Case report. Results. A twenty-four-year-old male with keratoconus underwent CXL treatment after epithelial removal with t-PTK using a Solid-State Laser system. No intra- or early postoperative complications were found. One month postoperatively, uncorrected visual acuity (UCVA) improved from 20/63 to 20/32 while best spectacle- corrected visual acuity (BSCVA) improved from 20/40 to 20/25. Corneal topography revealed a significant improvement which remained stable during the six-month followup period. Conclusions. Epithelial removal with t-PTK before CXL could improve patient's visual outcome.