Laser Direct Write Fabrication of Meta-Antennas for Electro-Optic Conversion

For electro-optic modulators, traveling wave designs are implemented due to the long interaction area necessary to efficiently modulate a signal with low voltages as a result of LiNbO 3 's modest electro-optic coefficient (r 33 =30 pm/V). However, with metamaterial inspired, electrically small resonator antennas, high field enhancements can be produced which allow the modulation of optical signals directly from the antennas, bypassing the need for a separate modulator For this work, Laser Direct Write (LDW) proved to be a useful tool in fabricating various meta-antenna array structures. The additive techniques of laser direct write, coupled with more traditional micromachining, have allowed the quick fabrication of these resonator meta-antennas so that the desired specifications, including resonant frequency and field enhancement, can be tested quickly and appropriate updates to the design can be made. This allows a designer to shift the resonant frequency and increase the field enhancement necessary to get the required device performance. The Laser Induced Forward Transfer (LIFT) technique was used initially for lower frequency designs (X-band); however, Laser Decal Transfer (LDT) was used subsequently for designs with higher frequencies by employing a digital mirror device to modulate the image of the beam. The resulting designs showed good fabrication consistency in terms of resonant frequency and comparable field enhancement to resonators fabricated through traditional lithography.