Project Description:

    Focused Laser Ablation - Writing on a Hair's Breadth

Ms. Lauranne Lanz of Oakland Mills High School was a high school student intern of the JHU/MRSEC in July 2002. Her project for the one-month internship under the supervision of Professor C. L. Chien was to use a focused laser beam as a dry etching tool.

The apparatus she used involved a high-power, pulsed UV (excimer) laser, focusing lenses, and a computer-controlled, moveable sample stage. The laser beam is focused by lenses to a fine spot, and effectively performs dry etching by ablating material from the illuminated spot. Ms. Lanz wrote a computer program to control the lateral movement of the sample stage to trace out patterns or words of her design in a continuous manner with sub-micron resolution. Simultaneously, her computer program controlled the triggering pulses for the laser light so that each sub-pattern or letter could be separately written.

Ms. Lanz first etched patterns and words of increasingly smaller sizes onto flat surfaces. She then explored the feasibility of labeling gemstones for microscopic identification purposes. Finally, on her own initiative, she successfully etched her name onto a strand of her hair as shown in Fig. 1.

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