Cavity-enhanced second-harmonic generation of narrowband 655 nm light

Skok, Krištof (author), Kaltenbaek, Rainer (mentor)

In the Laboratory for Quantum Optics and Quantum Foundations at the Faculty for Mathematics and Physics, University of Ljubljana, a new type of source of narrowband entangled photons is being build. Entangled photons will be generated via spontaneous parametric downconversion (SPDC), pumped by 655 nm light, which is produced from 1310 nm laser light via a non-linear optical phenomenon, second-harmonic generation (SHG). The process occurs in a non-linear crystal positioned in an actively stabilized optical cavity. The cavity is a resonator for laser light and enhances the light intensity inside, and consequently increasing the SHG conversion efficiency. The narrow cavity bandwidth leads to a narrow linewidth of 655 nm light, which is an essential design goal of the entire experiment. The thesis provides a theoretical treatment of second-harmonic generation, of optical cavities and of Pound-Drever-Hall technique, which is used for the active stabilization of the cavity. The experimental part describes the optical and electrical layout of the experimental setup and examines measurement results that characterize the bandwidth and quality of the optical cavity.

• Language: English
• Keywords: optično frekvenčno podvajanje, optični resonator, tehnika Pound-Drever-Hall, pasovna širina, finesa
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FMF - Faculty of Mathematics and Physics
• Year: 2022
• PID: 20.500.12556/RUL-141188
• COBISS.SI-ID: 122677251
• Publication date in RUL: 24.09.2022

Secondary language

• Language: Slovenian
• Title: Resonatorsko ojačano optično podvajanje za ozkopasovno 655 nm svetlobo

Abstract

V Laboratoriju za kvantno optiko in temelje kvantne fizike na Fakulteti za matematiko in fiziko, Univerza v Ljubljani, gradimo novo vrsto vira ozkopasovnih kvatno prepletenih fotonov. Nastanek kvantno prepletenih fotonov črpamo s svetlobo pri 655 nm, ki jo ustvarjamo z optičnim frekvenčnim podvajanjem iz laserske svetlobe pri 1310 nm. Do pretvorbe pride v nelinearnem kristalu, ki je postavljen v aktivno stabiliziran optični resonator. Optični resonator ojača intenziteto svetlobe v svoji notranjosti ter posledično izboljša izkoristek optičnega frekvenčnega podvajanja. Ozka pasovna širina resonatorja vodi do ozke spektralne širine 655 nm svetlobe, kar je ključna zasnovana lastnost celotnega eksperimenta. Magistrsko delo vključuje teoretično obravnavo optičnega frekvenčnega podvajanja, optičnih resonatorjev in tehnike Pound-Drever-Hall, ki jo uporabljamo za aktivno stabilizacijo resonatorja. Eksperimentalni del opisuje optično in električno shemo eksperimentalne postavitve in predstavi merske rezultate, ki karakterizirajo pasovno širino in kvaliteto optičnega resonatorja.

• Keywords: second-harmonic generation, optical cavity, Pound-Drever-Hall technique, free spectral range, cavity bandwidth, finesse