A new beam deflection angle amplification technique for mirage detection

Abstract

Abstract:A new technique has been developed for amplification of the photothermal beam deflection angle for mirage detection. This technique, based on a very simple operating principle, uses a cylindrical reflection mirror. The use of a new amplifier provided a signal-to-noise ratio approximately 10 times that obtained without the amplifier for equipment of the same size. By using the new amplifier, a mirage signal was obtained when a transistor array processed on a silicon wafer was measured.

Optimized frequency dependent photothermal beam deflection spectroscopy

“…The details about this procedure can be found in the literature [18,19], whereas the details about the fitting accuracy in the section 4.3. The fairly good agreement is observed between the determined (Ds = (0.85 ± 0.004) × 10 −4 m 2 s −1 , ks = 138 ± 8 W m −1 K −1 ) and literature values (Ds = 0.89 × 10 −4 m 2 s −1 , ks = 145 W m −1 K −1 ) of the sample's thermal properties and give an overall confirmation of our approach [8]. Figure 12 presents the dependences of amplitude and phase of the BDS signal on the modulation frequency of the excitation beam for CuFeInTe3 sample.…”

“…A flat sample with small lateral dimension (3 × 3 mm) was put in a 1 × 1 cm 2 quartz cell (Starna GmbH) and placed on a 3D translation stage (CVI, Model 2480M and 2488) that allows to vary the position in x, y and z (2 microns steep) direction to optimize the experimental configuration. The experiment was performed first in air, and was repeated after filling the cell with ACN as the coupling fluid with thermal conductivity k f = 0.180 W m −1 K −1 , thermal diffusivity 1.07 × 10 −7 m 2 s −1 , and dn/dT = −4.5 × 10 4 K −1 [8,9]. The corresponding values for air are 0.025 W m −1 K −1 , 0.232 × 10 −4 m 2 s −1 , and −0.87 × 10 −6 K −1 , respectively [8,9].…”

“…The experiment was performed first in air, and was repeated after filling the cell with ACN as the coupling fluid with thermal conductivity k f = 0.180 W m −1 K −1 , thermal diffusivity 1.07 × 10 −7 m 2 s −1 , and dn/dT = −4.5 × 10 4 K −1 [8,9]. The corresponding values for air are 0.025 W m −1 K −1 , 0.232 × 10 −4 m 2 s −1 , and −0.87 × 10 −6 K −1 , respectively [8,9].…”

“…Material characterization by the use of BDS has become an important area of research in photothermal science for the past few decades. This includes the determination of thermooptical [4], transport [5,6] and structural [7][8][9] properties of transparent or opaque materials with dimen-sions ranging from macro-down to nano-scale. Decreasing the sample sizes coincides with demands of high sensitivity, which is also crucial in case of weakly absorbing samples [10].…”

“…Decreasing the sample sizes coincides with demands of high sensitivity, which is also crucial in case of weakly absorbing samples [10]. Thus, many studies have been done on using different sensing fluids in which ThWs are induced and detected to increase the BDS signal [8][9][10][11] and the sensitivity of this technique. In such a situation the enhancement factor is a function of the thermodynamic and optical properties of the sensing fluids, among which organic liquids are par ticularly useful for this purpose, because of their relatively high refractive index gradients and low thermal conductivities.…”