Frequency and duty cycle modulation optimization in minimizing thermal accumulation effect in Z-scan measurement with high-repetition-rate laser

Zainal Abidin, Mohd Shahnan and Muhammad Noor, Ahmad Shukri and Abdul Rashid, Suraya and Mahdi, Mohd Adzir (2014) Frequency and duty cycle modulation optimization in minimizing thermal accumulation effect in Z-scan measurement with high-repetition-rate laser. Japanese Journal of Applied Physics, 53 (112702). pp. 112702-1. ISSN 0021-4922

PDF - Published Version Restricted to Repository staff only Download (606kB) | Request a copy

Abstract

In this study, we demonstrate the optimization of the chopper frequency and duty cycle in a Z-scan measurement with a 250MHz high-repetitionrate(HRR)femtosecond laser to minimize the thermal lensing effect due to cumulative heating of the sample. The result shows that such minimization can be achieved by keeping the modulated exposure time on the sample shorter than the thermal diffusivity decay time tc. The minimum chopper frequency fmin is predicted by relating the duty cycle factor F with tc, while maintaining stable peak and valley transmittances, i.e.,ΔTp and ΔTv, respectively. Furthermore, a lower fmin is obtained by taking a stable range of the peak–valley difference ΔTpv into consideration. The optimization allows for the low operational modulation frequency of Z-scan measurement with reduced thermal influence, thus enabling simple management of the thermal lensing effect.

Item Type:	Article (Journal)
Additional Information:	4148/38872
Uncontrolled Keywords:	thermal accumulation, Z-scan measurement, laser
Subjects:	Q Science > QC Physics T Technology > TA Engineering (General). Civil engineering (General) > TA1501 Applied optics. Lasers
Kulliyyahs/Centres/Divisions/Institutes (Can select more than one option. Press CONTROL button):	Kulliyyah of Engineering > Department of Electrical and Computer Engineering
Depositing User:	Mr. Mohd Shahnan Zainal Abidin
Date Deposited:	13 Nov 2014 10:55
Last Modified:	11 Jun 2018 12:43
URI:	http://irep.iium.edu.my/id/eprint/38872

Actions (login required)

View Item