Abstract: In a general aspect, a radio frequency (RF) measurement device includes first and second mode converters, each configured to convert a mode of the RF electromagnetic wave between a first RF waveguide mode and a second RF waveguide mode. The RF measurement device also includes an internal cavity between the first and second mode converters that contains a vapor or a source of the vapor. The vapor includes Ryberg atoms or molecules. The RF measurement device additionally includes an RF waveguide extending between the first and second mode converters and configured to carry the second RF waveguide mode through the internal cavity. In some variations, the RF waveguide includes first and second longitudinal portions disposed on respective, opposite sides of the device and configured to establish a target RF profile in an interaction region of the internal cavity.

Abstract: A photonic-crystal resonator (PhCR) and associated methods of design and manufacture. The PhCR includes spontaneous optical-pulse generation and includes a ring whose geometry is correlated to a mode structure or dispersion of the PhCR while also taking into account a desired type of nonlinear optical output from the PhCR, such as an optical frequency comb, or a particular type of pulse. The PhCR includes a periodic nanopatterning on an inner radial wall of its ring and is able to spontaneously generate a nonlinear optical output. The nanopatterning of the inner radial wall is designed to form a desired output, such as one of a classic soliton pulse that has a sech type temporal profile, or a gaussian profile, or a sink pulse profile.

Abstract: In a general aspect, a system for measuring radio frequency (RF) electromagnetic waves includes a laser system configured to generate plurality of input optical signals. The system also includes an RF measurement device having first and second mode converters and an internal cavity therebetween. The internal cavity contains a vapor that is configured to produce an output optical signal based on the plurality of input optical signals. The RF measurement device also includes an RF waveguide that extends between the first and second mode converters and is configured to carry the second RF waveguide mode through the internal cavity. The system also includes an optical detector system configured to generate a detector signal in response to receiving the output optical signal. The system additionally includes a signal processing system configured to generate data in response to receiving the detector signal.

Abstract: In a general aspect, a radio frequency (RF) measurement device includes first and second mode converters, each configured to convert a mode of the RF electromagnetic wave between a first RF waveguide mode and a second RF waveguide mode. The RF measurement device also includes an internal cavity between the first and second mode converters that contains a vapor or a source of the vapor. The vapor includes Ryberg atoms or molecules. The RF measurement device additionally includes an RF waveguide extending between the first and second mode converters and configured to establish a circular polarization of the RF electromagnetic wave in the internal cavity.

Abstract: A photonic device includes a substrate and a tantala ring resonator on the substrate. The tantala ring resonator has at least one of (i) a quality factor exceeding three million and (ii) a threshold power less than one hundred milliwatts. A frequency-comb generation method includes sweeping the output frequency of a laser coupled to a tantala ring resonator that has at least one of (i) a quality factor exceeding three million and (ii) a threshold power less than one hundred milliwatts.

Abstract: A tantala ring resonator includes a tantala ring resonator formed by ion-beam sputtering of tantalum pentoxide and exhibiting an optical quality factor in excess of 3×106, and a substrate to which the tantala ring resonator is attached. A method for fabricating nonlinear photonic devices includes depositing tantalum pentoxide with ion-beam sputtering to form a tantala layer onto a substrate, annealing the tantala layer, and etching the tantala layer to form a photonic device.