RU221839U1 - MID-IR RANGE SOLID-STATE LASER TUNABLE BY INTERFERENCE-POLARIZATION FILTER WITH LONGITUDINAL PUMPING BY FIBER LASER - Google Patents

Abstract

The utility model relates to laser technology, namely to a tunable mid-infrared (IR) laser with longitudinal pumping of a solid-state active element by a fiber laser. Such solid-state lasers can be used for mid-infrared spectroscopy, optoacoustic imaging systems, optical coherence tomography and surgical systems. The technical result that the proposed utility model is aimed at achieving is that when the radiation wavelength is adjusted, the direction of propagation of radiation of different frequencies does not change. This technical result is achieved by the fact that a tunable solid-state mid-IR laser with longitudinal pumping consists of a pump source; a resonator consisting of a solid spherical mirror, a focusing lens, an interference-polarization filter and a flat output plane mirror; and a solid-state active element installed along the optical axis of the resonator. A fiber laser with the ability to transmit its radiation into the resonator through a focusing fiber-optic system was used as a pump source; A sequential chain of a fiber light guide, a collimator and a focusing lens is used as a focusing fiber-optic system. Chalcogenide crystals doped with Cr ²⁺ ions, in particular a Cr ²⁺ :ZnSe crystal, or other compounds: Cr ²⁺ ZnS, Cr ²⁺ :CdSe, Cr ²⁺ :Cd _0.55 Mn ₀ were used as a solid-state active element of the resonator _.45 Te, Cr ²⁺ :CdS. 1 salary f-ly, 1 ill.

Description

The utility model relates to laser technology, namely to a tunable mid-infrared (IR) laser with longitudinal pumping of a solid-state active element by a fiber laser. Such solid-state lasers can be used for mid-infrared spectroscopy, optoacoustic imaging systems, optical coherence tomography and surgical systems.

State of the art

Known laser sources of radiation in the mid-IR range are lasers with pumping of the active element by fiber lasers, operating in continuous and pulsed modes. In this case, the wavelength of such systems is usually adjusted through the use of dispersion prisms and diffraction gratings. As a result, laser output radiation at different wavelengths exits the resonator at different angles, which complicates the further use of this radiation, in particular, its input into the fiber.

There are many known devices designed to produce laser lasing in the mid-IR spectral range. The closest analogue (prototype) of the proposed device can be considered a tunable solid-state laser in the mid-IR range with longitudinal pumping by a diode array, described in the author's publication by Toney T. Fernandez, Mikhail K. Tarabrin, Yuchen Wang, Vladimir A. Lazarev, Stanislav O. Leonov, Valeriy E. Karasik, Yurii V. Korostelin, Mikhail P. Frolov, Yurii P. Podmarkov, Yan K. Skasyrsky, Vladimir I. Kozlovsky, Cesare Svelto, Pasquale Maddaloni, Nicola Coluccelli, Paolo Laporta, and Gianluca Galzerano, "Thermo-optical and lasing characteristics of Cr2+-doped CdSe single crystal as tunable coherent source in the mid-infrared," Optical Materials Express, 7, 3815-3825, 2017, publication date 11/01/2017 Internet address: https://opg.optica. org/ome/fulltext.cfm?uri=ome-7-11-3815&id=374975), which is a solid-state mid-infrared laser longitudinally pumped by a fiber laser and consists of a pump source; a resonator consisting of a solid flat mirror, an intermediate spherical mirror, a diffraction grating installed in a Littrow configuration; and a solid-state active element installed along the optical axis of the resonator; A fiber laser with the ability to transmit its radiation into the resonator through a focusing fiber-optic system is used as a pump source. A sequential chain consisting of a fiber light guide, a collimator and a focusing lens is used as a focusing fiber-optic system. Using a diffraction grating installed in the Littrow configuration, a Cr:CdSe laser was tuned in the radiation wavelength range from 2.24 to 2.8 μm and an output power of up to 550 mW.

However, in the prototype, due to the chosen tuning method, radiation at different wavelengths exits the resonator at different angles, which makes it impossible to enter the output radiation into the fiber for transmission, for example, to the site of application during surgical manipulation.

Disclosure of utility model

The technical result that the proposed utility model is aimed at achieving is to ensure the same level of tuning width of the radiation wavelength while maintaining the direction of propagation of radiation of different wavelengths unchanged.

This technical result is achieved by the fact that a tunable solid-state mid-IR laser with longitudinal pumping consists of a pump source; a resonator consisting of a solid spherical mirror, a focusing lens, an interference-polarization filter and a flat output plane mirror; and a solid-state active element installed along the optical axis of the resonator. A fiber laser with the ability to transmit its radiation into the resonator through a focusing fiber-optic system was used as a pump source. A sequential chain consisting of a fiber light guide, a collimator and a focusing lens is used as a focusing fiber-optic system. Chalcogenide crystals doped with Cr ²⁺ ions, in particular a Cr ²⁺ :CdSe crystal, or other compounds: Cr ²⁺ :ZnS, Cr ²⁺ :ZnSe, Cr ²⁺ :Cd _0.55 Mn were used as a solid-state active element of the resonator _0.45 Te, Cr ²⁺ :CdS. Thanks to the use of an interference-polarizing filter installed at the Brewster angle, it is possible to adjust the wavelength by rotating the element in a plane perpendicular to the optical axis of the resonator, which allows maintaining the direction of propagation of radiation of different wavelengths.

List of figures

Figure 1 shows the structure of the interconnections of the elements of the device of the proposed solid-state laser in the mid-IR range.

Implementation of a utility model

In fig. 1 shows: 1 - pump source in the form of a fiber laser with a collimator, 2 - focusing element, 3 - blind spherical mirror, 4 - solid-state active element, 5 - lens, 6 - interference-polarizing filter, 7 - output flat mirror.

The proposed device works as follows. Radiation from the pump source 1 - fiber laser, passing through the fiber, enters the collimator, is focused on the solid-state active element 4 using the focusing element 2 through a spherical flat mirror 3, then the lasing radiation passes through the lens 5, passes through the interference-polarization filter 6 and after passing through the output mirror 7, it forms the output radiation of the solid-state laser. The wavelength of the output laser radiation is adjusted by rotating the interference-polarizing filter 6 in a plane perpendicular to the optical axis of the resonator. Due to the peculiarity of the filter's operation, when tuning the wavelength, there is no change in the propagation of the output laser radiation at different wavelengths, which makes it possible to enter this radiation into the fiber to transmit it, for example, to the area of medical procedures.

As a result of the author's experimental studies, it was established that when using an interference polarization filter instead of a diffraction grating, it is possible to adjust the radiation wavelength in the range from 2.1 to 3.1 microns using one element, which exceeds the parameters of the prototype laser system, and at the same time the output Radiation of different wavelengths propagates after the output mirror in one direction.

Thus, the proposed laser device can be used as a source of laser radiation with the possibility of wide tuning of the wavelength with a constant direction of propagation of radiation of different wavelengths for spectroscopy in the mid-IR range, for the creation of optoacoustic imaging systems, optical coherence tomography and surgical systems, etc. .

Claims (2)

1. A tunable solid-state mid-IR laser with longitudinal pumping, consisting of a pump source; a resonator consisting of a solid spherical mirror, a focusing lens, an interference-polarization filter and a flat output mirror; and a solid-state active element installed along the optical axis of the resonator through a focusing fiber-optic system; As a focusing fiber-optic system, a series circuit of a fiber light guide, a collimator and a focusing lens is used, characterized in that an interference-polarization filter is used as an element for tuning the radiation wavelength, and the output radiation of different wavelengths propagates in one direction. 2. Laser according to claim 1, characterized in that chalcogenide crystals doped with Cr ²⁺ ions are used as a solid-state active element of the resonator, in particular a Cr ²⁺ :ZnSe crystal or other compounds: Cr ²⁺ :ZnS, Cr ²⁺ : _CdSe , Cr ²⁺ :Cd _0.55 Mn _0.45 Te, ^{Cr 2+} _: CdS.