[19a-E205-1~12] 3.6 Ultrashort-pulse and high-intensity lasers

[19a-E205-7] Extraction of a field-enhancement factor from photoelectron spectra of a grating by optical field-emission

〇Tomoya Mizuno¹, Kengo Takeuchi¹, Keisuke Kaneshima¹, Nobuhisa Ishii¹, Teruto Kanai¹, Jiro Itatani¹ (1.Univ. Tokyo)

Keywords:mid-IR, optical field-emission, surface plasmons

We investigate optical field photoemission from a grating irradiated by mid-IR pulses. The total photoelectron yields clearly show resonant-like behavior under the condition of propagating surface plasmon resonance. This means that a near field, which is formed by localized surface plasmons at the grating ridge, is enhanced by resonantly produced propagating surface plasmons. The observed photoelectron spectra are well reproduced by a simple 1D model of a near field that contains two parameters: the field enhancement factor α, and the ridge radius r₀. As a result, we can extract two parameters, which determines a near field by comparing between measured and simulated photoelectron spectra.