Method and laser pulse enhancement apparatus for resonantly enhancing pulsed laser light for practical applications and sensitive measurements

Abstract

A method of passively enhancing pulsed laser light by coherent addition of laser pulses in an enhancement cavity (20) comprises the steps of generating a sequence of seed laser pulses (1) with a repetition frequency frep and a frequency comb spectrum (3) comprising frequency comb lines (4) with frequency comb line spacings equal to the repetition frequency frep, coupling the seed laser pulses (1) via a first plate-shaped coupling element (25) into an enhancement cavity (20) comprising at least two cavity mirrors (21, 22, 23, 24) having metallic surfaces and spanning a cavity beam path (26) with a resonator length L, wherein the enhancement cavity (20) has a fundamental transverse mode TEM00 and higher-order transverse cavity modes TEMnm, each with a series of cavity resonance frequencies (5), and a cavity offset frequency (6), and coherent superposition of the seed laser pulses (1) in the enhancement cavity (20), so that at least one enhanced circulating cavity pulse (2) per cavity length is generated, wherein the frequency comb spectrum (3) is a harmonic frequency comb spectrum (3) with a vanishing seeding comb offset frequency, the enhancement cavity (20) is adjusted such that a round-trip carrier-envelope phase slippage of the circulating cavity pulses 2 is equal to 360°/N for the fundamental transverse mode TEM00, N being an integer number equal to or above (2), and a frequency overlap is provided for a plurality of the cavity resonance frequencies (5) with a plurality of the frequency comb lines (4) along the frequency comb spectrum (3). Furthermore, a laser pulse enhancement apparatus and applications thereof, e. g. in field-resolved spectroscopy, are described.

Dependencies are inferred from the claim text.