Alison C. J. Glover

High-speed UV micro-machining of polymers with frequency-doubled copper vapor lasers

We report high-speed ultra-violet (UV) micro machining of polymers using a high beam quality frequency-doubled copper vapor laser (CTL). The characteristics of the UV laser source and beam delivery optics are described, Measurements of material removal rates have been made for a number of polymers. Results for UV-CVL micro-drilling of PETG and polyimide (kapton) show removal rates per pulse similar to other UV sources, but the high pulse repetition frequency of the UV-CVL results in much enhanced temporal material removal rates. >

Progress in high-speed UV micro-machining with high repetition rate frequency-doubled copper vapour lasers

We report on progress in uv micro-machining with high repetition rate (4.5 kHz) frequency-doubled copper vapour lasers (CVLs). Characteristics of drilling 2 to 300 micron diameter holes in several materials, including polyethylene and polyimide, will be discussed.We report on progress in uv micro-machining with high repetition rate (4.5 kHz) frequency-doubled copper vapour lasers (CVLs). Characteristics of drilling 2 to 300 micron diameter holes in several materials, including polyethylene and polyimide, will be discussed.

UV Micromachining Using Copper Vapour Lasers

UV output powers in excess of IW at 255nm can readily be generated by SHG from single, medium-scale copper vapour lasers. The high PRF and high beam quality makes the frequency-doubled CVL an ideal source for many UV micromachining applications such as drilling micro-orifices in polymers at high production rates.

High-speed micromachining with UV-copper vapor lasers

Ablation rate characteristics (etch rates) are presented for micro-machining of polyimide (kapton) and PETG using a frequency doubled Copper Vapor Laser (uv-CVL) at 255 nm and a frequency quadrupled Nd:YLF (4*Nd:YLF) laser at 261 nm. A comparison is made of the etch rates obtained by continuous ablation at 4.25 kHz with the uv-CVL with rates obtained for bursts of pulses with 2 second intervals between bursts. These results suggest that the observed decrease in ablation depth per pulse after a number of pulses for fluences above 0.6 J/cm2 is due to attenuation of succeeding laser pulses by the plume of previously-ejected material. Preliminary results of the effect of sample temperature on ablation rates are also presented.

The frequency-doubled copper vapour laser - An alternative source for high repetition rate micro-machining

We report on the output characteristics of a high repetition rate, high beam quality UV source, based on a frequency doubled copper vapour laser (CVL), and present preliminary results on the precision drilling of thin polymer films.We report on the output characteristics of a high repetition rate, high beam quality UV source, based on a frequency doubled copper vapour laser (CVL), and present preliminary results on the precision drilling of thin polymer films.

Ablation threshold and etch rate measurements in high-speed ultra-violet (uv) micro-machining of polymers with uv-copper vapour lasers

Material removal rates (etch rates) are given for the ultra-violet (uv) ablation of polyimide, mylar and PETG by uv-Copper Vapour Lasers (CVLs) operating at 255 nm and at pulse repetition rates (prfs) from 4.25 to 20 kHz for fluences in the range 0.08 to 2.2 J/cm2. These results and the extrapolated thresholds are compared with those obtained by excimer laser ablation at similar wavelengths and fluences, and with the ablation model of Srinivasan, Smrtic and Babu. Qualitative results for PMMA, which has lower absorption at this wavelength, are also presented. Possible thermal effects of ablation at these high prfs are discussed.Material removal rates (etch rates) are given for the ultra-violet (uv) ablation of polyimide, mylar and PETG by uv-Copper Vapour Lasers (CVLs) operating at 255 nm and at pulse repetition rates (prfs) from 4.25 to 20 kHz for fluences in the range 0.08 to 2.2 J/cm2. These results and the extrapolated thresholds are compared with those obtained by excimer laser ablation at similar wavelengths and fluences, and with the ablation model of Srinivasan, Smrtic and Babu. Qualitative results for PMMA, which has lower absorption at this wavelength, are also presented. Possible thermal effects of ablation at these high prfs are discussed.

High-speed precision UV drilling with frequency-doubled copper vapor lasers

The copper vapor laser (CVL) is an efficient, high average power, high pulse rate visible laser, emitting in the green and the yellow. Previous applications of CVLs have been limited to those requiring a high power visible laser source but with no specific need for high output beam quality. Recently we have made substantial progress in understanding the factors that influence CVL beam quality. As a result we are now able to achieve efficient non-linear frequency conversion to produce a number of ultraviolet wavelengths with near- diffraction limited beam quality. The high repetition rate and low divergence uv output of the frequency-doubled CVL makes it an attractive alternative to the excimer laser for a number of applications, including high-speed precision hole-drilling, cutting and scoring in polymers and for deep-uv photolithography. We report here recent developments that have led to efficient generation of uv wavelengths from copper vapor lasers and we demonstrate its potential as a laser source for high-speed precision ultraviolet micromachining.