Qhov Dav ntawm Pulse Lasers

Qhov dav ntawm lub zog (pulse width) yog hais txog lub sijhawm ntawm lub zog, thiab qhov ntau thiab tsawg feem ntau yog txij li nanoseconds (ns, 10^-9vib nas this) mus rau femtoseconds (fs, 10^-15vib nas this). Cov lasers pulsed nrog cov pulse widths sib txawv yog tsim rau ntau yam kev siv:

- Lub zog luv luv (Picosecond/Femtosecond):

Zoo tagnrho rau kev ua kom raug ntawm cov ntaub ntawv tawg yooj yim (piv txwv li, iav, sapphire) kom txo cov kab nrib pleb.

- Ntev Pulse Width (Nanosecond): Haum rau kev txiav hlau, vuam, thiab lwm yam kev siv uas xav tau cov teebmeem thermal.

- Femtosecond Laser: Siv rau hauv kev phais qhov muag (xws li LASIK) vim tias nws tuaj yeem txiav tau meej thiab tsis muaj kev puas tsuaj rau cov nqaij ib puag ncig.

- Ultrashort Pulses: Siv los kawm txog cov txheej txheem dynamic ceev heev, xws li kev co molecular thiab cov tshuaj lom neeg.

Qhov dav ntawm lub zog cuam tshuam rau kev ua haujlwm ntawm lub laser, xws li lub zog siab tshaj plaws (P_{lub ncov}= lub zog ntawm lub zog/qhov dav ntawm lub zog. Qhov luv dua qhov dav ntawm lub zog, qhov siab dua lub zog siab tshaj plaws rau tib lub zog ntawm lub zog ib leeg.) Nws kuj tseem cuam tshuam rau cov teebmeem thermal: qhov dav ntawm lub zog ntev, zoo li nanoseconds, tuaj yeem ua rau muaj kev sib sau ua ke ntawm cov khoom siv thermal, ua rau yaj lossis puas tsuaj los ntawm thermal; qhov dav ntawm lub zog luv, zoo li picoseconds lossis femtoseconds, ua rau "kev ua haujlwm txias" nrog txo cov cheeb tsam cuam tshuam los ntawm cua sov.

Cov lasers fiber feem ntau tswj thiab kho qhov dav ntawm lub zog siv cov txheej txheem hauv qab no:

1. Q-Switching: Tsim cov nanosecond pulses los ntawm kev hloov pauv cov resonator poob tsis tu ncua kom tsim cov high-energy pulses.

2. Hom-Xauv: Tsim cov picosecond lossis femtosecond ultrashort pulses los ntawm kev sib dhos cov hom longitudinal hauv lub resonator.

3. Cov Modulators lossis Cov Nyhuv Tsis Zoo: Piv txwv li, siv Nonlinear Polarization Rotation (NPR) hauv cov fibers lossis cov absorbers saturable los nias qhov dav ntawm lub zog.