Microcontroller based high power 809-nm diode laser design for biophotonics applications

Abstract

High power diode lasers irradiating near infrared light (800-980-nm) have a widerange of applications in many branches of medicine due to the developments in the lasertechnology for the last 20 years. The ability of having high penetration property in soft tissues and enhancing indocyanine green (ICG) dye induced approaches in biophotonicsapplications provides possible usage of 809-nm diode laser for diagnostic and therapeuticpurposes. In this thesis, a high power 809-nm diode laser system was designed andmanufactured. System was consisting of 809-nm high power diode laser module with 10 W output power, current source unit, current sensor, switch mode power supply unit, microcontroller based controller unit, and fiber coupling. Diode laser driver systemprovides current to 809-nm diode laser module from voltage controlled current source inorder to generate continuous wave 809-nm laser light. A current sensor was used to sense the operating current of laser diode for current feedback process of controller unit.Microcontroller based controller unit provided the control of whole system and itfacilitated the user to access all the functionalities of the system. The user interfaceprogram was developed in C programming language to set diode current in amperes and duration in seconds via a PC. During laser operation, values of the diode current anddiode temperature were controlled simultaneously and monitored by the interfaceprogram. The output power of the laser light was measured by using a powermeter and itwas seen that the microcontroller based diode laser system was working accurately and efficiently.|Keywords: 809-nm diode laser, Microcontroller, ICG, Continuous laser light.