Integrated microwave-to-optical single-photon transducer with strain-induced electro-optic material
Transducers and methods of making the same include a substrate having a cavity with a diameter that supports whispering gallery modes at a frequency of an input signal. A focusing structure in the cavity focuses the electric field of the input signal. A resonator directly under the focusing structure has a crystalline structure that generates an electro-optic effect when exposed to electrical fields. An electric field of the input signal modulates an output signal in the resonator via the electro-optic effect.
1. A transducer, comprising:
a substrate having a cavity with a diameter that supports whispering gallery modes at a frequency of an optical input signal;
a focusing structure in the cavity; and
an optical resonator directly under the focusing structure, having a crystalline structure that generates an electro-optic effect when exposed to electrical fields, wherein at a junction of the focusing structure with the optical resonator, an electrical field of the optical input signal modulates an optical output signal in the optical resonator via the electro-optic effect.
2. The transducer of claim 1 , wherein the cavity is cylindrical and the focusing structure is a center pin that is coaxial with the cavity.
3. The transducer of claim 1 , further comprising a superconducting film that is formed directly on an inner surface of the cavity and on an outer surface of the focusing structure.
4. The transducer of claim 1 , wherein the optical resonator is formed from a first material having grooves in a top surface with a second material formed in the grooves, wherein the second material creates a strain in a crystalline structure of the first material to generate the electro-optic effect in the optical resonator.
5. The transducer of claim 4 , wherein the optical resonator comprises an optical disc structure.
6. The transducer of claim 4 , wherein the optical resonator comprises an optical ring structure.
7. The transducer of claim 1 , wherein the focusing structure is a cylindrical pin comprising a surface facing toward the optical resonator, the surface having a ridge along an outer circumference.
8. The transducer of claim 1 , further comprising another cavity underneath the optical resonator having a same diameter as the cavity in the substrate.
9. The transducer of claim 1 , wherein the cavity is resonant with whispering gallery modes at a microwave frequency and the optical resonator is resonant at an optical frequency.