Laser interference lithography for the collective fabrication of quartz-microcylinders

The use of optical tweezers and spin angular momentum transfer to birefringent particles allows new nano-scale mechanical measurements in systems where torque and rotation are relevant parameters. There is a growing interest in developing simple, fast and inexpensive protocols to produce a large number of sub-micron scale cylinders of quartz, a positive uniaxial birefringent crystal, to be employed for such angular measurements in optical tweezers. Here we present a novel method based on laser interference lithography that fulfills these requirements, producing arrays of quartz cylindrical particles over several cm2 surface with an efficient microfabrciation process. These particles were successfully used to apply and measure optical torque in an optical torque wrench.