Low-noise tunable deep-ultraviolet supercontinuum laser

Callum R Smith,Abubakar I Adamu,Mattia Michieletto,Patrick Bowen,Peter M Moselund,Asbjørn Moltke,Christos Markos,Ole Bang

doi:10.1038/s41598-020-75072-y

Callum R Smith, Abubakar I Adamu + Show 6 more

Open Access

https://doi.org/10.1038/s41598-020-75072-y

Copy DOI

Abstract

The realization of a table-top tunable deep-ultraviolet (UV) laser source with excellent noise properties would significantly benefit the scientific community, particularly within imaging and spectroscopic applications, where source noise has a crucial role. Here we provide a thorough characterization of the pulse-to-pulse relative intensity noise (RIN) of such a deep-UV source based on an argon (Ar)-filled anti-resonant hollow-core (AR HC) fiber. Suitable pump pulses are produced using a compact commercially available laser centered at 1030 nm with a pulse duration of 400 fs, followed by a nonlinear compression stage that generates pulses with 30 fs duration, 24.2 μJ energy at 100 kHz repetition rate and a RIN of < 1%. Pump pulses coupled into the AR HC fiber undergo extreme spectral broadening creating a supercontinuum, leading to efficient energy transfer to a phase-matched resonant dispersive wave (RDW) in the deep-UV spectral region. The center wavelength of the RDW could be tuned between 236 and 377 nm by adjusting the Ar pressure in a 140 mm length of fiber. Under optimal pump conditions the RIN properties were demonstrated to be exceptionally good, with a value as low as 1.9% at ~ 282 nm. The RIN is resolved spectrally for the pump pulses, the generated RDW and the broadband supercontinuum. These results constitute the first broadband RIN characterization of such a deep-UV source and provide a significant step forward towards a stable, compact and tunable laser source for applications in the deep-UV spectral region.

Highlights

The realization of a table-top tunable deep-ultraviolet (UV) laser source with excellent noise properties would significantly benefit the scientific community, within imaging and spectroscopic applications, where source noise has a crucial role
The phase-matching frequency occurs on the other side of the zero-dispersion wavelength (ZDW), the position of the resonant dispersive wave (RDW) can be tuned by varying the gas pressure within the hollow core (HC) fiber
Another study quotes a relative intensity noise (RIN) value of 0.4% measured in the frequency domain, for 1030 nm pulses compressed to the single-cycle regime using a two-stage anti-resonant hollow-core (AR HC) fiber compression s cheme[22]

Summary

Introduction

The realization of a table-top tunable deep-ultraviolet (UV) laser source with excellent noise properties would significantly benefit the scientific community, within imaging and spectroscopic applications, where source noise has a crucial role. HC PCFs can include fibers with guiding based on a photonic b andgap[11], a Kagomé lattice[12], or a negative curvature anti-resonant (AR) structure[13] The latter two of these designs can provide low-loss transmission over a broad bandwidth, and a relatively low anomalous dispersion environment, which are very attractive attributes for ultrashort pulse compression and extreme nonlinear o ptics[14]. This concept has been employed using a range of gas species to generate UV radiation with broadband guiding HC P CFs16–22 The majority of these experiments relied on a titanium-sapphire laser to provide the pump pulses, resulting in an inherently large footprint and low repetition rate of 1 kHz to achieve the required pulse energy. This study did not involve RDW generation and the UV component of the spectrum is not isolated and measured

Methods

Results

Conclusion