RP Photonics logo
RP Photonics
Encyclopedia
Consulting Software Encyclopedia Buyer's Guide

Short address: rpp-con.com

Dr. Paschotta, the founder of RP Photonics, supports your R & D with his deep expertise. Save time and money with efficient support!

Short address: rpp-soft.com

Powerful simulation software for fiber lasers and amplifiers, resonator design, pulse propagation and multilayer coating design.

Short address: rpp-enc.com

The famous Encyclopedia of Laser Physics and Technology provides a wealth of high-quality scientific and technical information.

Short address: rpp-bg.com

In the RP Photonics Buyer's Guide, you easily find suppliers for photo­nics products. As a supp­lier, you can profit from enhanced entries!

Learn on lasers and photonics every day!
VL logo part of the
Virtual
Library

Ultrashort Pulses

<<<  |  >>>  |  Feedback

Buyer's Guide

Use the RP Photonics Buyer's Guide to find suppliers for photonics products! You will hardly find a more convenient resource.

Ask RP Photonics for advice on any aspect of ultrashort pulse generation with lasers, the propagation of ultrashort pulses, or measurements on or with ultrashort pulses.

Definition: optical pulses with durations of picoseconds or less

German: ultrakurze Pulse

Optical pulses as generated in mode-locked lasers can be extremely short, particularly for passive mode locking. There is no commonly accepted definition of “ultrashort”, but usually this label applies to pulses if their pulse duration is at most a few tens of picoseconds, and often in the range of femtoseconds.

Note that ultrashort pulses should not be called “ultrafast” – they are not faster (do not have a higher velocity) than longer pulses. They do, however, make it possible to investigate ultrafast processes (→ ultrafast optics), and can be used for fast optical data transmission. In the latter case, “fast” means a high data rate, not actually a high velocity.

Ultrashort pulses are usually generated with passively mode-locked lasers, but sometimes also with optical parametric amplifiers (possibly using a supercontinuum as input) or with free electron lasers. It is also possible to start with longer pulses and apply some method of pulse compression. The article on ultrafast lasers lists some important areas of ultrashort pulse generation, including the generation of few-cycle pulses, where the pulse duration is only a small multiple of an optical cycle (few-cycle pulses).

Concerning their spatial properties, ultrashort pulses are usually generated in the form of laser beams. Essentially, they can be focused to very small spots just as it is possible with stationary beams. However, various limitations come into play particularly in the regime of few-cycle pulses. For example, the broad optical bandwidth of such pulses leads to problems with the chromatic dispersion of lens materials, which leads to chromatic aberrations of the focusing optics unless special correction techniques are employed. This can lead to complicated spatio-temporal effects, which may make the focused pulse to have a larger duration than the pulse before focusing. Possible measures against such distortions include the use of reflective or diffractive (instead of refractive) optics as well as the careful compensation of various types of aberrations, e.g. using suitable lens combinations.

The propagation of ultrashort pulses in media gives rise to a range of interesting phenomena, particularly when optical nonlinearities are involved. This can be investigated with, e.g., pulse propagation modeling. Relevant physical effects can be chromatic dispersion, the Kerr effect, Raman scattering, and gain saturation, to name just some important examples.

There are various methods for pulse characterization, allowing the measurement of fundamental pulse parameters such as the pulse duration, but also “complete” characterization in the sense that the whole time-dependent electric field and the spectral phase can be obtained. The results can be visualized in various ways, e.g. with graphs of time- or frequency-dependent functions, or with spectrograms.

See also: pulses, pulse propagation modeling, pulse characterization, pulse duration, parabolic pulses, sech2-shaped pulses, mode locking, mode-locked lasers, ultrafast lasers, femtosecond lasers, ultrafast laser physics

Category: pulses

How do you rate this article?

Your general impression: don't know poor satisfactory good excellent
Technical quality: don't know poor satisfactory good excellent
Usefulness: don't know poor satisfactory good excellent
Readability: don't know poor satisfactory good excellent
Comments:

Found any errors? Suggestions for improvements? Do you know a better web page on this topic?

Spam protection: (enter the value of 5 + 8 in this field!)

If you want a response, you may leave your e-mail address in the comments field, or directly send an e-mail.

If you like our website, you may also want to get our newsletters!

cover of SPIE Field Guide cover of SPIE Field Guide cover of SPIE Field Guide

Dr. Paschotta, author of this encyclopedia, has also published three books in the SPIE Field Guide series:

- Field Guide to Lasers

- Field Guide to Laser Pulse Generation

- Field Guide to Optical Fiber Technology

You can order these books on the SPIE website – just click on one of the images.

arrow

Have you seen the
RP Photonics Buyer's Guide?

It lists many hundreds of suppliers for photonics products, and is just one mouse click away from the extremely popular Encyclopedia of Laser Physics and Technology:

Our Buyer's Guide is what you need:

And surely you will remember where to find this useful resource again!

Suppliers: get your free entries, and enhanced visibility with paid entries.

Tutorials on Fiber Optics

See our tutorials "Passive Fiber Optics" and "Fiber Amplifiers" – two very comprehensive and useful resources!

 

anniversary

Thin-film Optics Software

Analyze and optimize dichroic and dispersive mirrors, AR coatings, filters, thin-film polarizers, rugate filters, VECSELs etc. with RP Coating!

coating design

RP Photonics Buyer's Guide

Do you know a better place to find suppliers for photonics items? Search by product or by supplier.

Suppliers, show your products with free or enhanced entries!

New Fiber Optics Software!

RP Fiber Calculator software

RP Fiber Calculator – a convenient tool for calculations on optical fibers -- offered for free within the 10-year anniversary of RP Photonics, and also as a PRO version with even more powerful features!