• Femtosecond laser writing of the depressed cladding buried channel waveguides in ZnS crystal 

      Okhrimchuk, A.; Smayev, M.; Likhov, V.; Sorokin, Evgeni; Tolstik, Nikolai; Sorokina, Irina T (Chapter, 2018)
      We report the first direct laser-writing of buried channel waveguides in ZnS. A depressed cladding waveguide with propagation loss of 0.62 dB/cm at 1030 nm allowed to obtain spectral broadening under femtosecond-pumping ...
    • Femtosecond Operation and Random Quasi-Phase-Matched Self-Doubling of Ceramic Cr:ZnSe Laser 

      Sorokin, Evgeni; Sorokina, Irina T (Chapter, 2010)
      A 100-fs Cr:ZnSe laser, based on a ceramic active medium, generates 100 mW at 215 MHz repetition rate around 2450 nm. Co-propagating second-harmonic pulse at 1225 nm is simultaneously generated due to random quasi-phase-matching ...
    • Femtosecond operation and self‐doubling of Cr:ZnS laser 

      Sorokin, Evgeni; Sorokina, Irina T; Tolstik, Nikolai (Chapter, 2011)
      Prismless dispersion‐controlled Cr:ZnS laser generates first femtosecond (110 fs) pulses at 180 MHz repetition rate around 2400 nm with average power 200 mW. Copropagating second‐harmonic pulse at 1200 nm is simultaneously ...
    • Femtosecond SESAM-modelocked Cr:ZnS laser 

      Sorokin, Evgeni; Tolstik, Nikolai; Schaffers, Kathleen I.; Sorokina, Irina T (Journal article; Peer reviewed, 2012)
      We report self-starting femtosecond operation of a 180-MHz SESAM-controlled prismless Cr:ZnS laser around 2400 nm at open air and room temperature. Dispersion compensation was achieved by a combination of bulk materials ...
    • Graphene mode-locked Cr: ZnS chirped-pulse oscillator 

      Tolstik, Nikolai; Pospischil, Andreas; Sorokin, Evgeni; Sorokina, Irina T (Journal article; Peer reviewed, 2014)
      We report the first to our knowledge high-energy graphene mode-locked solid-state laser operating in the positive dispersion regime. Pulses with 15.5 nJ energy and 42 nm spectral bandwidth with 0.87 ps duration were obtained ...
    • Graphene Mode-locked Cr:ZnS Laser with 41 fs Pulse Duration 

      Tolstik, Nikolai; Sorokin, Evgeni; Sorokina, Irina T (Journal article; Peer reviewed, 2014)
      We report the ultrashort-pulse Cr:ZnS laser mode-locked by graphene-based saturable absorber mirror. Using the combination of bulk material and a chirped mirror, we demonstrate the shortest reported so far mid-IR pulses ...
    • High-energy Mid-Infrared Cr:ZnS Chirped-pulse oscillator 

      Tolstik, Nikolai; Sorokin, Evgeni; Sorokina, Irina T (Chapter; Peer reviewed, 2013)
      Femtosecond coherent light sources emitting in the mid-infrared are of particular interest for a number of applications like environmental sensing, medicine, metrology, material processing and telecommunications. Among the ...
    • Kerr-Lens Mode-locked Cr:ZnS Laser 

      Sorokin, Evgeni; Tolstik, Nikolai; Sorokina, Irina T (Chapter, 2012)
      The first Kerr-Lens mode-locked Cr:ZnS laser generates the shortest and highest-energy mid-IR near transform-limited pulses of 69 fs duration at 550 mW output power. The 3.7 nJ pulses have 193 nm wide spectrum around 2.39 µm
    • Kerr-lens mode-locked Cr:ZnS laser 

      Tolstik, Nikolai; Sorokin, Evgeni; Sorokina, Irina T (Journal article; Peer reviewed, 2013)
      We report the soft-aperture Kerr-lens mode-locked Cr:ZnS laser, generating 550 mW of 69 fs nearly transform-limited pulses at 2.39 μm wavelength. The pulse energy reached 3.8 nJ at 145 MHz repetition rate, limited by the ...
    • MBE-grown Cr:ZnS Thin Film Laser Media 

      Tolstik, Nikolai; Sorokin, Evgeni; Karhu, Eric Andrew; Polyakov, Stanislav; Gibson, Ursula; Sorokina, Irina T (Chapter, 2016)
      We report results of spectroscopic analysis of the first first laser-quality MBE-grown Cr:ZnS films. Comparison of spectral-luminescent properties with bulk Cr:ZnS indicates their good laser properties, opening the way ...
    • Mid-IR ultrashort pulsed fiber-based lasers 

      Sorokina, Irina T; Dvoyrin, Vladislav; Tolstik, Nikolai; Sorokin, Evgeni (Journal article; Peer reviewed, 2014)
      We review the latest breakthroughs in ultrafast fiber laser technology in the mid-IR wavelength range ≥2 μm. In particular, we concentrate on two novel laser systems built around passively mode-locked Tm:fiber lasers and ...
    • Nonlinear Propagation of mid-IR Femtosecond Pulses in ZBLAN Fiber 

      Tolstik, Nikolai; Sorokin, Evgeni; Kalashnikov, Vladimir; Sorokina, Irina T (Chapter, 2012)
      We demonstrate environmentally protected delivery of high-power femtosecond mid-IR pulses in a single-mode ZBLAN fiber by soliton formation. A 70-fs Cr:ZnS laser at 2.4 µm reaches this regime already at ~1.5 nJ launched ...
    • Optical Coatings as Active Media for Mid-Infrared lasers 

      Karhu, Eric Andrew; Tolstik, Nikolai; Sorokin, Evgeni; Furtula, Vedran; Sorokina, Irina T.; Gibson, Ursula (Chapter, 2016)
      Thin films of Cr and Fe-doped ZnS with high infrared transparency have been deposited by molecular beam epitaxy and show optical properties suitable for use as active media in mid-infrared laser applications.
    • Principles, advances and applications of ultrafast mid-infrared lasers 

      Sorokina, Irina T; Sorokin, Evgeni (Chapter, 2009)
      The talk reviews principles and advances in generation and applications of ultrashort pulses and frequency combs directly from the solid-state oscillator based on Cr2+ZnSe laser, and highlights radical efficiency and ...
    • Soliton absorption spectroscopy in normal-dispersion lasers 

      Kalashnikov, Vladimir; Sorokin, Evgeni; Sorokina, Irina T (Chapter, 2010)
      An all-normal-dispersion oscillator with narrowband intracavity absorption acquires spectral features which follow the index of refraction of the absorber, as confirmed by experimental obsevation. Compared to the conventional ...
    • Soliton delivery of mid-IR femtosecond pulses with ZBLAN fiber 

      Tolstik, Nikolai; Sorokin, Evgeni; Kalashnikov, Valdimir L; Sorokina, Irina T (Journal article; Peer reviewed, 2012)
      We demonstrate environmentally protected delivery of highpower femtosecond mid-IR pulses in a single-mode ZBLAN fiber by soliton formation. A 70-fs Cr:ZnS laser at 2.4 µm reaches this regime already at ~2 nJ launched pulse ...
    • Spectral Broadening of mid-IR Femtosecond Pulses in Highly Germanium Doped Fiber 

      Tolstik, Nikolai; Klimentov, Dmitry; Dvoyrin, Vladislav; Sorokina, Irina T; Sorokin, Evgeni; Kalashnikov, Vladimir (Chapter, 2012)
      We demonstrate significant spectral broadening of femtosecond mid-IR pulses directly from the oscillator in a simple step-index single-mode highly Ge-doped fiber at only 150 pJ pulse energies in the spectral window around 2.38 µm.
    • Spectral-luminescent properties of vapor deposited Cr:ZnS thin films and their application as saturable absorbers for 1.5-μm erbium lasers 

      Tolstik, Nikolai; Sorokin, Evgeni; Karhu, Eric Andrew; Gorbachenya, Konstantin N.; Polyakov, Stanislav; Kisel, Victor E.; Kuleshov, Nikolai V.; Furtula, Vedran; Gibson, Ursula; Sorokina, Irina T (Journal article; Peer reviewed, 2018)
      We report the results of the extensive spectral-luminescent characterization including concentration quenching analysis of the first laser-quality vapor-deposited Cr:ZnS films, and demonstrate their use as saturable ...
    • Supercontinuum generation in Mid-IR using Chalcogenide and Germanate Nonlinear Fiber 

      Tolstik, Nikolai; Sorokin, Evgeni; Kalashnikov, Vladimir; Klimentov, Dmitry; Dvoyrin, Vladislav; Sorokina, Irina T (Journal article; Peer reviewed, 2013)
      We demonstrate mid-infrared (mid-IR) supercontinuum generation with bandwidth from 2 to 2.8 μm at 20 dB below the peak in nonlinear step-index chalcogenide fiber using femtosecond mid-IR pulses directly from the oscillator. ...
    • Three-optical-cycle frequency comb centered around 4.2 µm using OP-GaP-based half-harmonic generation 

      Sorokin, Evgeni; Marandi, Alireza; Schunemann, PG; Fejer, M; Sorokina, Irina T; Byer, Robert L. (Chapter, 2016)
      We report a broadband mid-infrared frequency comb with three-optical-cycle pulse duration centered around 4.2 µm, with up to 220 mW average power, via OP-GaP-based half-harmonic generation pumped by mode-locked fiber lasers.