A. N. Kireev

Stable Similariton Generation in an All-Fiber Hybrid Mode-Locked Ring Laser for Frequency Metrology

Ultrashort pulse lasers constitute an important tool in the emerging field of optical frequency metrology and are enabling unprecedented measurement capabilities and new applications in a wide range of fields, including precision spectroscopy, atomic clocks, ultracold gases, and molecular fingerprinting. We demonstrate the generation of stable 127-fs self-similar pulses at a central wavelength of 1560 nm with 7.14-mW average output power. Similariton lasers have a low repetition rate deviation in the averaging time interval 1-1·103 s, a low relative intensity noise -120 dBc/Hz (30 Hz to 10 kHz), a narrow single comb line width of 32 kHz, and high reliability. Thus, such lasers are highly promising for further development of the stabilized combs and open up a robust and substantially simplified route to synthesizing low-noise microwaves.

Testing of Cr:ZnSe Laser with Intracavity Methane Cell in 77-300 K Temperature Range

The mid-IR cw tunable solid state two-mode Cr²⁺:ZnSe laser with intracavity methane cryocell was developed. The laser was applied for sub-Doppler spectroscopy of (υ₁+υ4) vibrational-rotational band of methane and observation of narrow resonances of saturated dispersion at λ = 2.36 μm. The new technique of low pressure methane gas cooling was used instead of liquid nitrogen “jacket” design applied in our previous work. Parameters of saturated dispersion resonances were estimated in 77-300 K temperature range. The experiments confirmed that laser with the new “dry cooled” methane cell has prospectives for reaching a short-term frequency stability at the level of 10^-15-0^-16 and can be used as a compact device.

Tunable CW Solid-State Mid-IR Cr 2+ :CdSe Single Crystal Laser with Diode Laser Array Pumping

We demonstrate the first Cr2+:CdSe single crystal laser with diode laser array pumping. Laser efficiency of 12% with output power of 280 mW was obtained. Tunable CW operation was observed in 2450 - 3060 nm range.

Diode array-pumped mid-infrared cw Cr2+:CdSe laser

The operation of a room-temperature, solid-state, Cr-doped CdSe continuous-wave laser is demonstrated. Longitudinal pumping with a continuous-wave diode laser array at 1.94 µm produced a broadband output of 200 mW at 2.6 µm with an incident power slope efficiency of 6.4%.

Comb characterization of Erbium All-fiber Hybrid Mode-locked ultra-short pulse Ring laser for Frequency Metrology

Stable 92.6 fs dechirped self-similar pulses were obtained at 1560 nm with 11.2 mW average output power. Similariton laser has low repetition rate deviation at 1 - 103 s, a single comb linewidth of 110 kHz and high reliability, which makes it promising for further development of the stabilized comb.

Methane based microwave reference oscillator

Two microwave reference oscillators based on a He-Ne/CH<inf>4</inf> optical frequency standard (λ = 3.39 μm) and femtosecond Er fiber laser (λ = 1.55 μm) optical-to-microwave frequency divider were created. The measurements have demonstrated short term frequency instability (Allan deviation) of the output microwave signal at 1.5 GHz at the level of 1×10⁻¹⁴ (τ = 1 s). Interrogative oscillator with such stability is attractive for application in Cs and Rb atomic fountains.

All-fiber hybridly mode-locked similariton ring laser for frequency metrology

We demonstrate the generation of stable 127 fs self-similar pulses at a central wavelength of 1560 nm with 7.14 mW average output power. Similariton lasers have low repetition rate deviation in the averaging time interval 1-1·103 s, a low relative intensity noise -125 dBc/Hz, a narrow single comb line width of 32 kHz, and high reliability. Thus, such lasers are highly promising for further development of the stabilized combs.

Generation of Supercontinuum and Spectrum Broadening in Holey Fibers Subjected to Radiation from Continuous Femtosecond Visible and Infrared Lasers

Supercontinuum generation in holey fibers manufactured at the University of Bath (Great Britain) and at the Institute of Radioengineering and Electronics of the Russian Academy of Sciences is produced through use of a Ti:sapphire femtosecond laser. Broadening of the radiation spectrum of a Cr:forsterite femtosecond laser (λ = 1250 nm) is observed in these fiber samples. The present study is part of a program intended for the creation of an optical femtosecond synthesizer stabilized relative to a methane optical frequency standard (λ = 3390 nm).