Optimizing the photothermal signal: effects of the detector position and pinhole radius in mode-mismatched Z -scan

Applied Optics 2026

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Authors: Komna Fata, K.S. Gadedjisso-Tossou, Dam-Bé Lardja Douti, Basma Khammari, Kosi M Novidzro, M. A. Mohou, abdul Rahman, Khalid Hassan Ibnaouf, Riadh Hannachi, Humberto Cabrera
DOI: 10.1364/ao.583195
Cited by: 1
References: 22

Abstract

The pump-probe mode-mismatched thermal lens Z -scan technique is used to investigate the effects of detector position (L) and pinhole radius ( ρ 0 ) on the thermal lens (TL) signal. Theoretical analysis shows that the TL signal is sensitive to both parameters, with optimal performance at a detector distance of ∼20cm and a pinhole radius of 0.02 cm. As the pinhole radius increases, the TLS peak shifts to higher L values and the signal amplitude decreases. Experimental measurements with pinhole radii of 0.02, 0.05, 0.075, and 0.1 cm, using an ethanol solution, exhibit good agreement with the theoretical model, validating its reliability. Experimental optimization validated the theoretical model, revealing the significant influence of aperture size and detector position.

Fields of Study & Subjects

Thermography and Photoacoustic Techniques Thermal properties of materials Photoacoustic and Ultrasonic Imaging

Publication details

Journal / source
Applied Optics
Publisher
Optica Publishing Group
Volume
65
Issue
6
Pages
1794–1794
Publication date
21 January 2026
Language
EN