Fig. 1. Ultrasonic jet system

Fig. 2. Simulation of single period ultrasonic coupled jetta

Fig. 3. Ultrasonic high frequency fragmentation effect

Fig. 4. Principle diagram of ultrasound-assisted femtosecond laser processing

Fig. 5. Machining drawing

Fig. 6. Effect of ultrasonic frequency on the depth and depth to width ratio of etched quartz microgroove

Fig. 7. Effect of ultrasonic power on the depth and depth to width ratio of etched quartz microgroove

Fig. 8. Effect of gas inlet pressure on the depth and depth to width ratio of etched quartz microgroove

Fig. 9. SEM image of femtosecond laser etched quartz microgroove slag attached to the wall surface

Fig. 10. Comparison of the width of femtosecond laser etching quartz microgroove with or without ultrasonic gas jet assisted

Fig. 11. Comparison of the depth of femtosecond laser etching quartz microgroove with or without ultrasonic gas jet assisted

Fig. 12. Micromorphology of quartz microgroove wall etched by femtosecond laser with or without ultrasonic assistance