Laser Chemical Etching of Spectrometer Gratings

We plan to use Laser Chemical Etching (LCE, or also called Laser Microchemical etching, LMC), a direct etch process capable of true high resolution 3-D etching with micron resolution, almost arbitrary depth, high aspect ration, and extremely smooth surface finish (less than 40nm RMS), to produce convex gratings for use in Offner spectrometers. LMC is vastly superior to Excimer Laser Micromachining in essentially every aspect, from LMC's much higher control, uniformity of etch, and reproducibility to LCE's ultra-clean etching with only gaseous by-products (no debris). It has a number of attributes that can make it a better choice than e-beam lithography if production is an issue. We will demonstrate that LMC will allow the production of convex infrared gratings without the fabrication limitations of e-beam/optical lithography and without the limitations of ion milling, conventional etching, excimer laser micromachining, mechanical ruling, or conventional replication processes.