Abstract
We explore the use of room-temperature ionic liquids (ILs) as Raman wavelength converters. ILs provide an engineerable framework to design suitable liquids for wavelength conversion over a broad spectral range, through careful selection of the molecular structures of the IL anions and cations so that specific characteristics can be obtained, such as a desirable Raman shift, low Brillouin scattering, and good optical transmission in the pump and Stokes wavelengths. Applying such criteria, we demonstrate that 1-ethyl-3-methylimidazolium dicyanamide (EMIM DCA) is an effective medium for conversion of 532-nm pulses from a Q-switched YAG laser to 603 nm. This corresponds to an approximate 2200 shift, which can be used to generate mid-infrared radiation through subsequent difference frequency generation for optical pumping of lasers. Threefold-higher Raman conversion efficiency is obtained in EMIM DCA compared with water under identical conditions in a proof-of-principle single-pass conversion setup, resulting in an efficient generation of multimillijoule, <6 ns duration, high-quality orange laser pulses in a wavelength region that is difficult to access at high energies. Consequently, we examine ILs representing two other classes of Raman-active functional groups and obtain conversion up to the fifth-order Stokes shift and first anti-Stokes shift. Through the tunable selection of their components and their useful dynamical properties, ILs provide a platform for efficient, simple, and alignment-tolerant high-energy Raman shifting with numerous industrial and technological applications.
- Received 16 June 2022
- Accepted 8 December 2022
DOI:https://doi.org/10.1103/PhysRevApplied.19.014052
© 2023 American Physical Society
Physics Subject Headings (PhySH)
synopsis
A Salt-Based Laser Color Converter
Published 19 January 2023
Artificial salts that are liquid at room temperature can be used to efficiently tune the wavelength of a laser source.
See more in Physics