Lecture

Pulsed Lasers: Phase Matching Techniques

Graph Chat

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

In course

CH-360: Atoms and radiation

This course discusses the interaction between atoms and visible electro-magnetic radiation and introduces the main instrumentation for light detection and spectroscopy. The principles of LASER light sources are described, providing notions of nonlinear and ...

Description

This lecture covers the principles of pulsed lasers, focusing on phase matching techniques in nonlinear optics. It discusses the classification of second-order nonlinear processes, birefringent materials, the index ellipsoid, and the normal modes in anisotropic materials. The lecture also explores acousto-optical and electro-optical modulators, Q-switching, and mode-locking phenomena. It delves into the generation of short light pulses, transient lasing behaviors, and dispersion control in ultrashort pulses. Additionally, it explains the measurement of ultrashort pulses using techniques like FROG and the challenges in amplifying ultrashort pulses.

Official source

Ontological neighbourhood

Physics

Optics: Nonlinear optics

Related concepts (32)

Ultrashort pulse

In optics, an ultrashort pulse, also known as an ultrafast event, is an electromagnetic pulse whose time duration is of the order of a picosecond (10−12 second) or less. Such pulses have a broadband optical spectrum, and can be created by mode-locked oscillators. Amplification of ultrashort pulses almost always requires the technique of chirped pulse amplification, in order to avoid damage to the gain medium of the amplifier. They are characterized by a high peak intensity (or more correctly, irradiance) that usually leads to nonlinear interactions in various materials, including air.

Mode locking

Mode locking is a technique in optics by which a laser can be made to produce pulses of light of extremely short duration, on the order of picoseconds (10−12 s) or femtoseconds (10−15 s). A laser operated in this way is sometimes referred to as a femtosecond laser, for example, in modern refractive surgery. The basis of the technique is to induce a fixed phase relationship between the longitudinal modes of the laser's resonant cavity. Constructive interference between these modes can cause the laser light to be produced as a train of pulses.

Acousto-optic modulator

An acousto-optic modulator (AOM), also called a Bragg cell or an acousto-optic deflector (AOD), uses the acousto-optic effect to diffract and shift the frequency of light using sound waves (usually at radio-frequency). They are used in lasers for Q-switching, telecommunications for signal modulation, and in spectroscopy for frequency control. A piezoelectric transducer is attached to a material such as glass. An oscillating electric signal drives the transducer to vibrate, which creates sound waves in the material.

Chirped pulse amplification

Chirped pulse amplification (CPA) is a technique for amplifying an ultrashort laser pulse up to the petawatt level, with the laser pulse being stretched out temporally and spectrally, then amplified, and then compressed again. The stretching and compression uses devices that ensure that the different color components of the pulse travel different distances. CPA for lasers was introduced by Donna Strickland and Gérard Mourou at the University of Rochester in the mid-1980s, work for which they received the Nobel Prize in Physics in 2018.

Femtosecond pulse shaping

In optics, femtosecond pulse shaping refers to manipulations with temporal profile of an ultrashort laser pulse. Pulse shaping can be used to shorten/elongate the duration of optical pulse, or to generate complex pulses. Generation of sequences of ultrashort optical pulses is key in realizing ultra high speed optical networks, Optical Code Division Multiple Access (OCDMA) systems, chemical and biological reaction triggering and monitoring etc.

Related lectures (42)

Active-Passive Modelocking: Fundamentals and Applications

Covers the fundamentals of active and passive modelocking in ultrafast lasers.

Introduction to Ultrafast Optics

Introduces the fundamentals of ultrafast optics, covering light pulses, dispersion, mode-locked lasers, and chirped pulse amplification.

Ultrafast lasers: modelocking

Explores modelocking in ultrafast lasers, covering pulse width relationships, chirped pulses, and fiber coupling design.

Mode Locking Techniques: Generating High Power Lasers

Explains mode locking techniques to achieve high peak power in lasers.

Antennas: Openings and Radiation