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25LS-O-2
LASER SYSTEMS AND MATERIALS
Optical pulse compressor using Bayfol based holographic gratings
I. Zhluktova, V. Kamynin, R. Okun, V. Tsvetkov
Prokhorov General Physics Institute of the Russian Academy of Sciences, 38 Vavilov St., Moscow 119991, Russia
Main author email address: romanokun@yandex.ru
Laser sources of highly-chirped subnanosecond pulses are perspective for further amplification to mJ-level energies. Application of such sources reduces high peak power intensity and prevents nonlinear broadening and optical elements damage. One of the main points in such solutions is to compress amplified pulses to spectral limited durations. To solve this problem, usually, pulse compressors are used. The key elements of which are often diffraction gratings [1]. Among the materials that allow creating low-selective and high efficiency diffraction gratings, the most common and commercially successful is Bayfol HX 200 holographic photopolymer. Thus, the main interest of this work refers to the calculation and development of ultrashort pulse compressor based on holographic diffraction gratings recorded in the Bayfol HX 200 photopolymer.
In this work, we used an all-fiber ytterbium laser operating in the passive mode-locking regime as the master oscillator (MO). The fundamental pulse repletion rate is 1 MHz with a pulse duration of 120 ps. At the output of the MO, we have chirped dissipative solitons with the maximum intensity of the spectrum close to the wavelength of 1063 nm [2].
The first issue studied in our work is related to the possibility of application of holographic optical elements recorded in Bayfol HX 200 photopolymer in the near infrared (IR) range, since at the moment the vast majority of applications of the material are limited to the visible range of wavelengths. The paper shows that the refractive index modulation of holograms recorded in Bayfol HX 200 does not significantly decrease in the near IR range compared to the visible range of the spectrum. Thus, Bayfol HX 200 with a thickness of 16 microns allows to obtain holograms with the diffraction efficiency up to 100% in the near IR range. This allows it to be used as a material for diffraction gratings in the laser operating spectral range.
The second question is the calculation of the compressor parameters and simulation of pulse compression. The characteristics of diffraction elements, dimensions, efficiency and dispersion of compressor are calculated. The layout of the proposed compressor is shown in fig. 1(a). Finally we realized and discussed pulse compression in the proposed compressor. As a result, we obtained an oscillogram of the compressed pulse MO up to 27.5 ps, which is a hardware function of the registering pair photodetector-oscilloscope (Thorlabs DX25CF & Tektronix DPO75002SX) (fig. 1(b)). Thus, for the first time, as far as we know, an ultrashort pulse compressor using holographic gratings on the Bayfol HX 200 holographic polymer has been demonstrated.
ALT'22
diffraction grating 2 roof mirror
a b
Fig. 1. Compressor layout (a), pulse oscillogram (b)
[1] J. Liu, X. Shen, S. Du and R. Li, Multistep pulse compressor for 10s to 100s PW lasers, Optics Express, 29(11), 17140-17158, (2021).
[2] I. Zhluktova, S. Filatova, A. Trikshev, V. Kamynin, and V. Tsvetkov, All-fiber 1125 nm spectrally selected subnanosecond source, Applied Optics, 59(29), 9081-9086, (2020).
