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Starch is a polymer derived from plants that have various applications. There are various types of starch available like potato, maize, tapioca, and wheat, etc. We have studied and successfully differentiated tapioca and maize starch using polarized light microscopy and bright field techniques with the help of Iodine staining. Starch granules are suspended in aqueous or non-aqueous media for polarized light and bright field microscopy. The botanical source of the starch is identified according to the shape and size of granules, granule surface marking, the position of hilum, iodine staining, and the presence of maltase crosses under polarized light.

Time-resolved thermal lens (TL) technique is used to measure the heat transfer in pure methanol and its binary mixtures with hexane. We used dual-beam mode mismatched pump-probe scheme where a femtosecond laser beam of 1560 nm was used as a pump beam, and its frequency-doubled 780 nm beam was used as probe beam. TL Signal decreases with increasing concentration of hexane in the binary mixture. On higher concentration of Hexane in binary mixture then we have found convective heat transfer mode was absent. At 40%-60% methanol hexane mixture, we observed a sudden curious jump in TL signal.

The popularity of artificial neural networks (ANNs) of great depth and Quantum computing have led to many speculations as to their convergence. We enumerate barriers to utilizing qubit networks for deep learning architectures. We also describe the criteria for an effective usage of qubit networks and then assert that the bottleneck in their implementation is a lack of quantum algorithms for utilizing the topology of a deep neural network.

Femtosecond Thermal Lens Spectroscopy (FTLS) has been developed to a level of sensitivity that can have molecule specific response due to convection as demonstrated experimentally and theoretically. Within this framework, we show here that it is possible to use this technique for sensitive detection of liquid versus gas phase. Experimental demonstration is made with a single beam FTLS experiment of traces of iodine in pentane mixture in liquid versus its vapor phase.

Mode Mismatched Pump-Probe spectroscopic method was employed to examine the thermally induced nonlinear optical properties of methanol and its binary mixtures. The heat transfer mechanism in methanol and its binary mixtures with carbon tetrachloride (CCl 4 ) at different concentrations of methanol is investigated. Methanol has the highest Thermal Lens (TL) signal, and CCl 4 does not have any TL signal at all. However, the presence of CCl 4 modulates the TL signal of the binary mixture. The time-domain shift in TL signal is observed for different concentrations of methanol, which indicates the unusual molecular behavior in the binary mixture.

Though a single ultrashort pulse has inconceivable thermal effect, highly repetitive femtosecond lasers often result in some heating effects. Instead of fretting over the thermal effect, we have used this to develop the time-resolved photothermal lens spectroscopy for molecular sensitivity.

Femtosecond laser pulses have been shaped in a programable manner for coherent control at molecular level and for several coherent optical processes that have resulted in applications to fast switching, data compression, ultrasensitive detection, computing, etc. Optical and quantum interaction and their detection remain at the forefront of all such efforts. Typically, however, it is not common for ultrashort time to be connected to ultrasmall dimension. Use of femtosecond optical tweezers (FOTs) makes this connection possible. We have developed a novel on-the-fly calibration method of FOT that enables in situ control and contactless measure of absolute temperature and viscosity at nanoscale dimensions. Such measurements and control at the nanoscale have been challenging since the present techniques can only provide relative off-line measurements that are of low spatial resolution. Such spatiotemporal control with ultrashort pulses provides the possibility of manipulation at nanoscale that can yield several interesting results that include visualization of colloidal aggregation in real time, computational logical operation in localized zone that is then reset with the subsequent pulse train. We simultaneously apply the high temporal sensitivity of position autocorrelation and equipartition theorem to precisely measure and control in situ temperature and the corresponding microrheological property around the focal volume of the trap at high spatial resolution. The FOTs use a single-beam high repetition rate laser for optical trapping to result in finer temperature gradients in comparison to the continuous-wave laser tweezers. Thermal effects are often treated delirious and most spectroscopy efforts remain in removing them. We have, on the other hand, used highly repetitive femtosecond laser heating to develop time-resolved photothermal lens spectroscopy that provide molecule level sensitivity.

Since long the thermal effects have not been much explored in the optical trapping theory, in this paper, we are establishing the effects of optically induced thermal nonlinearity in the medium of optical trapping in the Rayleigh regime for both continuous wave and a pulsed laser. For a single beam, optical tweezers with high numerical aperture (N.A.) objectives are used as a routine. In such a tight focusing scenario, both optical nonlinearity and thermal effects may prevail in the cases of continuous wave (C.W.) and pulsed laser-mediated optical trapping events. In this paper we will introduce the effects sequentially, starting from optical nonlinearity and methods to implement this effect and subsequently introduce the thermal nonlinearity in the medium. The effects are significantly different when compared between CW and pulsed optical tweezers and will be discussed in detail in this paper.

We present a new method to utilize photo-thermal effect at nano-volume dimension, to measure viscosity, which could be useful to eventually correlate to in-vivo conditions. We present our measurements using high repetition rate low average power femtosecond laser induced conditions under which the photo-thermal effect is highly influence by the convective mode of heat transfer. This is especially important in absorbing liquids. This is unlike the typical photo-thermal conditions not involving such ultrashort pulses. Typical thermal processes involve only conductive mode of heat transfer and are phenomenological in nature. Inclusion of convective mode results in some additional molecular characteristics to the thermal process. We measure the traditional thermal lens studies with femtosecond pulse train through geometric beam divergence of a collimated laser beam co-propagating with the focused heating laser beam. The refractive index gradient in the sample due to the focused heating laser creates a thermal lens, which is measured. On the other hand, the same heat gradient from the focusing heating laser beam generates a change in local viscosity in the medium, which changes the trapped stiffness of an optically trapped microsphere in its vicinity. We use co-propagating femtosecond train of laser pulses of wavelength 1560 nm and 780 nm for these experiments. From the bulk thermal studies, we show that use of water as sample provides us the advantage to use conductive mode of heat transfer even with femtosecond pulse train excitation.

Ultrafast pump-probe technique has been invoked to understand the liquid:liquid interface by using a cyanine dye dissolved in dimethyl sulfoxide (DMSO), interfaced with neat diethyl-ether (Et2O). We show that the dynamics of the dye gets slow down on moving from the bulk dye solution in DMSO towards the interface with neat-diethyl ether. Hence we get an alternate picture of interface by looking at the time constants. Four time constants were used for fitting the experimental data which are assigned to be coherent artifact, vibrational cooling, intermediate state time and finally ground state recovery time. The drastic change in signal was observed at a distance of 0.1 mm from the interface. The decreasing time constants from bulk to near interfaced solution strongly suggests involvement of heterogeneity in the system because of the penetration of diethyl ether through the interface into the DMSO layer where the dye is dissolved, which strongly affects the dynamics at near the interface of the DMSO with neat-diethyl ether layer (at 0.1 mm distance from the interface).

The critical role of the detection aperture size on the measurement of thermal lens signals has been explored by using mode-mismatched pump-probe thermal lens spectroscopy in pure methanol. Femtosecond laser pulses at 1560 nm are used to create thermal lens signal, which is simultaneously probed by a collinear 780 nm pulse train through a partially open aperture of different sizes placed after the sample. The trend in the time resolved thermal lens signals reveals that aperture size allowing less than half of the incident probe light is critical in providing accuracy of the thermal lens spectroscopy.