Silicon Lenslet Arrays for Microwave Background (SLAMB)

Silicon lenslet arrays are a necessary component in the fourth generation of DOE-funded investigations into the nature of cosmic microwave background radiation. Studying detailed physical properties of the cosmic background allow us to understand the origins of the early universe and the future universe’s behavior. In the current generation of experiments, silicon lenslet arrays are assembled by hand. The next round of proposed instruments requires 10 times more lenslets to achieve the science goals. Hand assembly is impractical at this volume and makes installation cumbersome. ColdQuanta proposes to build each lenslet array from a single silicon wafer to form a robust component. ColdQuanta will develop a scalable manufacturing process for the lenslet arrays suitable to meet the technological and scientific goals of the proposed studies. The Phase I effort will adapt ColdQuanta’s current precision silicon micro-milling processes to the specific machining techniques required to meet the production needs of the upcoming experiments. By taking advantage of the advances in high speed ceramic machining, the symmetric nature of the array, and parallel chemical processing, ColdQuanta will optimize the production process flow to demonstrate a path to high volume production and produce a silicon lenslet array prototype. Lawrence Berkeley National Laboratory will characterize the prototype to the requirements of the current generation of experiments to ensure suitability. In Phase II, we will employ the production sequence to fabricate the silicon lenslets arrays as required by the specific needs of the fourth generation of cosmic microwave background experiments. These specialized processing capabilities, once demonstrated, will enable other research groups requiring silicon optics for prototype systems or production, especially for millimeter wave instrumentation or radio frequency astronomy experiments. Projects requiring large quantities of silicon optics will be especially well served. These techniques will be further adapted by ColdQuanta to compact Ultra High Vacuum (UHV) systems for atomic, molecular and optical (AMO) physics and the generation of cold and ultra-cold matter. The application of high speed machining techniques will make these systems less expensive and more reliable. This work could help applications such as the next generation of high-performance atomic clocks, inertial sensors, gravimeters, electric field sensors, and magnetometers that are portable, robust, and deployable. Industries using these devices include telecommunications (atomic clocks), defense and aviation (inertial sensors), and geology and civil engineering (gravimeters and magnetometers). The silicon anti-reflection techniques developed under this effort will have immediate application to electric field sensors based on Rydberg atoms. Electric field sensors have a wide variety of applications including antenna calibration, design and manufacturing of radar and communication systems, millimeter-wave detection, and microwave circuit design and testing.