I have been working in the field of tunable diode laser spectroscopy (TDLS) for the measurement of gas parameters ever since I started my PhD from the Indian Institute of Technology Gandhinagar, India in August 2010. My journey at Strathclyde began in February 2017 when I started working on an EPSRC funded project named Fibre Laser Imaging for gas Turbine Exhaust Species (FLITES). This project had Rolls-Royce, Shell, Universities of Manchester, Southampton, and Strathclyde as collaborators and in this project gases coming out from the exhaust plume of the combustion engine had to be measured with a high spatial and temporal resolution. This information would provide an insight into the complex phenomenon of combustion in modern gas turbines and would enable an assessment of novel gas fuels.

Since February 2018, I have been working on two projects, simultaneously. The first is an extension of the FLITES project where we have to take this project to a product stage. The second project that I am working on is the use of photoacoustic measurement (PAM) techniques for the identification of endothelial dysfunction (ED) which is an early indicator of atherosclerosis and other cardio vascular diseases. Therefore, a low cost non-invasive reliable rapid screening method for the detection of ED can be greatly helpful in avoiding cardiovascular disorders through an early identification of the potential patients.

Apart from these projects I also have an interest in imaging, both photoacoustic as well as TDLS, and I am looking forward to work on it in the near future.

• Tunable diode laser spectroscopy
• Photoacoustic imaging

• A. Upadhyay and A. L. Chakraborty, "Calibration-free 2f WMS with in situ real time characterization of a laser modulated at its phase quadrature and with 2f RAM nulling," Optics Letters (Jul 2015).
• A. Upadhyay, D. Wilson, M. Lengden, A. L. Chakraborty, G. Stewart and W. Johnstone, "Demonstration of calibration-free WMS measurement of gas parameters with in-situ real-time characterization of laser parameters using cw-DFB-QCL, VCSEL and DFB lasers," IEEE Photonics Journal (Jan 2017).
• A. Upadhyay and A. L. Chakraborty, "Residual amplitude modulation method implemented at the phase quadrature frequency of a 1650 nm laser diode for line shape recovery of methane," Sensors Journal, IEEE (Feb 2015).
• A. S. Zarin, A. L. Chakraborty and A. Upadhyay, "Absolute noninvasive measurement of CO2 mole fraction emitted by E. coli and S. aureus using calibration-free 2f WMS applied to a 2004 nm VCSEL," Optics Letters (May 2017).