Enhanced surface thermal lensing for absorption evaluation and defect identification of optical films

Li, Shuhong; He, Hongbo; Shan, Yongguang; Li, Dawei; Zhao, Yuanan; Zhang, Fan

doi:10.1364/ao.49.002417

Cited by 9 publications

(7 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the simulation, the radius of the pump beam is a ¼ 150 μm and the thermal diffusivity of the Cr film is k th ¼ 2:9 × 10 −5 m 2 =s, so the characteristic time is t c ¼ 0:193 ms calculated by Eq. (15). From Fig.…”

Section: Temporal Characteristicsmentioning

confidence: 97%

“…It has been successfully applied to many diverse areas, such as materials science [13], optical film coating defect inspection [14,15], thermophysical parameters measurement [16][17][18], subnanoliter measurement [19], spectroscopy [20,21], and microscopy [22]. Two types of TL techniques have been reported: mode-matched [23] and mode-mismatched [24] configurations.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Femtosecond laser-induced thermal lens effect in chromium film

2010

View full text Add to dashboard Cite

The thermal lens (TL) effect induced by femtosecond laser pulses in chromium film is reported. A Fresnel diffraction theory is used to explain the TL effect. The intensity profile of the TL calculated by the theoretical model is in agreement with the experimental results. The contrast ratio of the TL is defined to describe the TL effect, and we find that the maximum contrast ratio of the TL effect is obtained when the probe beam is recorded at a characteristic distance. The dependence of the contrast ratio of the TL on different pump laser power levels and delay times is also investigated. Numerical simulations are also consistent with the experimental results.

show abstract

Section: Temporal Characteristicsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Femtosecond laser-induced thermal lens effect in chromium film

2010

View full text Add to dashboard Cite

show abstract

“…5,6 Surface thermal lens technique, first reported by Kuo and Munidasa 7 and Satio et al, 8 has also been developed to be a highly sensitive photothermal technique and was widely used in absorptance and surface displacement measurements of optical components. [9][10][11][12][13] Due to the development of the mode-mismatched thermal lens configuration, 14,15 the sensitivity of surface thermal lens technique has been considerably improved. Moreover, the use of top-hat beam excitation, first proposed by Li et al 9 and late adopted by Astrath et al, 16,17 has further improved the sensitivity of surface thermal lens technique, with a maximum sensitivity enhancement factor of 2.…”

Section: Introductionmentioning

confidence: 99%

“…Currently, He-Ne laser operated at 633 nm is commonly used as the probe beam in almost all surface thermal lens or in general thermal lens experiments or instruments. [9][10][11][12][13]16,17,20 On the other hand, with the rapid development of highpower laser technique, 21 the absorption loss of optical laser components used in high-power laser systems becomes a crucial parameter due to the high sensitivity of the laserinduced damage threshold and thermal distortion to the absorption loss. The absorption of laser power by optical laser components causes temperature rise inside the laser components and results in thermal expansion (thermal distortion) and thermal stress or melting of the laser components.…”

Section: Introductionmentioning

confidence: 99%

Sensitivity enhancement of surface thermal lens technique with a short-wavelength probe beam: Experiment

Zhang

2015

Review of Scientific Instruments

View full text Add to dashboard Cite

Surface thermal lens is a highly sensitive photothermal technique to measure low absorption losses of various solid materials. In such applications, the sensitivity of surface thermal lens is a key parameter for measuring extremely low absorption. In this paper, we experimentally investigated the influence of probe beam wavelength on the sensitivity of surface thermal lens for measuring the low absorptance of optical laser components. Three probe lasers with wavelength 375 nm, 633 nm, and 1570 nm were used, respectively, to detect the surface thermal lens amplitude of a highly reflective coating sample excited by a cw modulated Gaussian beam at 1064 nm. The experimental results showed that the maximum amplitude of surface thermal lens signal obtained at corresponding optimized detection distance was inversely proportional to the wavelength of the probe beam, as predicted by previous theoretical model. The sensitivity of surface thermal lens could, therefore, be improved by detecting surface thermal lens signal with a short-wavelength probe beam.

show abstract

“…The uniformity of optical coatings becomes more and more important as large-diameter optical devices are used widely. The photothermal deflection technique [4,5] and surface thermal lens technique [6,7] can be used in absorption uniformity measurement of optical thin films. The test accuracy and sensitivity need to be improved further.…”

Section: Introductionmentioning

confidence: 99%

Study on the absorption uniformity of optical thin films based on the photothermal detuning technique

2012

View full text Add to dashboard Cite

Absorption loss in optical components, particularly in optical coatings, is a limiting factor in high-power laser applications. The uniformity of optical coatings becomes more and more important as large-diameter optical devices are used widely. In this paper, the photothermal detuning technique used for absorption uniformity measurement of optical thin films is developed for the first time. Experiments are conducted with a highly reflective coating used in 514 nm to measure the photothermal detuning signal and to evaluate the absorption at 514 nm by detecting the spectral shift with a probe beam at a wavelength of 632.8 nm. The relative absorption at different points on the sample surface can be measured by moving the sample two-dimensionally, and we use the measured data to make the absorption image. The results show that the designed experimental system can be used to analyze the absorption uniformity of optical coatings. The obtained images reflect the absorption uniformity of the sample well. The absorption uniformities of the two samples analyzed in this experiment are different. The film coated on fused silica is better. The research provides a powerful and convenient tool for absorption uniformity measurement of optical thin film.

show abstract

Enhanced surface thermal lensing for absorption evaluation and defect identification of optical films

Cited by 9 publications

References 11 publications

Femtosecond laser-induced thermal lens effect in chromium film

Femtosecond laser-induced thermal lens effect in chromium film

Sensitivity enhancement of surface thermal lens technique with a short-wavelength probe beam: Experiment

Study on the absorption uniformity of optical thin films based on the photothermal detuning technique

Contact Info

Product

Resources

About