Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
  • G01N21/41—Refractivity; Phase-affecting properties, e.g. optical path length
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B82—NANOTECHNOLOGY
  • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
  • B82Y10/00—Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J1/00—Photometry, e.g. photographic exposure meter
  • G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
  • G01J1/44—Electric circuits
  • G01J2001/4413—Type
  • G01J2001/442—Single-photon detection or photon counting

Definitions

• Embodiments of the present disclosure relate to determining optical properties of a dielectric sample, and more specifically, to a quantum cross-resonator spectrometer.
• the present invention is an apparatus, comprising: a first electromagnetic resonator; a second electromagnetic resonator intersecting the first resonator, thereby defining an intersection area, the first and the second resonator each comprising at least one interface; a source configured to generate an electromagnetic source signal; at least a first detector; at least one input/output means in electromagnetic communication with the source, the at least one interface of the first resonator and the at least one interface of the second resonator.
• the at least one input/output means is configured to: based on a source signal, generate a first input signal and a second input signal; apply to the first and the second signals an input amplitude ratio and an input relative phase shift, thereby generating a first transformed input signal and a second transformed input signal; transmit the first transformed input signal to the at least one interface of the first resonator, thereby generating a first output signal therefrom; and transmit the second transformed input signal to the at least one interface of the second resonator, thereby generating a second output signal therefrom.
• the at least one input/output means is further configured to: receive the first output signal from the first resonator and the second output signal from the second resonator; apply to the first and the second output signals an output amplitude ratio and an output relative phase shift, wherein the output amplitude ratio is an inverse of the input amplitude ratio and the output phase shift is a sign-reverse of the input phase shift, thereby generating a first transformed output signal and a second transformed output signal; and transmit at least the first transformed output signal to the at least the first detector, the at least first detector configured to generate at least a first result signal.
• the present invention is an apparatus, comprising: a first electromagnetic resonator; a second electromagnetic resonator intersecting the first resonator, thereby defining an intersection area, the first and the second resonator each comprising an input interface and an output interface; a source configured to generate an electromagnetic source signal; a first detector and a second detector; an input means in electromagnetic communication with the source, the input interface of the first resonator and the input interface of the second resonator; and an output means in electromagnetic communication with the output interface of the first resonator, the output interface of the second resonator, and the first and the second detectors.
• the input means is configured to: based on a source signal, generate a first input signal and a second input signal; apply to the first and the second signals an input amplitude ratio and an input relative phase shift, thereby generating a first transformed input signal and a second transformed input signal; transmit the first transformed input signal to the input interface of the first resonator, thereby generating a first output signal therefrom; and transmit the second transformed input signal to the input interface of the second resonator, thereby generating a second output signal therefrom.
• the output means is configured to: receive the first output signal from the first resonator and the second output signal from the second resonator; apply to the first and the second output signals an output amplitude ratio and an output relative phase shift, wherein the output amplitude ratio is an inverse of the input amplitude ratio and the output phase shift is a signreverse of the input phase shift, thereby generating a first transformed output signal and a second transformed output signal; and transmit the first transformed output signal to the first detector, and transmit the second transformed output signal to the second detector, the first and the second detectors configured to generate a first result signal and a second result signal.
• the present invention is a method of determining an index of refraction of a sample, the method comprising: providing the apparatus of the first example embodiment, wherein the intersection area is adapted to receive the sample and evanescently couple thereto, the sample having a complex index of refraction defined by a real part and an imaginary part; disposing the sample at the intersection area; causing the source to generate the source signal; causing the at least one input/output means to: based on the source signal, generate a plurality of input signal pairs, each input signal pair comprising a first and a second input signals; for each input signal pair, apply to the first and the second input signals an input amplitude ratio and an input relative phase shift, thereby generating a transformed input signal pair, the transformed input signal pair comprising a first and a second transformed input signals; and for each transformed input signal pair, transmit the first transformed input signal to the at least one interface of the first resonator, and transmit the second transformed input signal to the at least one interface of the
• the present invention is a method of determining an index of refraction of a sample, the method comprising: providing the apparatus of the second example embodoment, wherein the intersection area is adapted to receive the sample and evanescently couple thereto, the sample having a complex index of refraction defined by a real part and an imaginary part; disposing the sample at the intersection area; causing the source to generate the source signal; causing the input means to: based on the source signal, generate a plurality of input signal pairs, each input signal pair comprising a first and a second input signals; for each input signal pair, apply to the first and the second input signals an input amplitude ratio and an input relative phase shift, thereby generating a transformed input signal pair, the transformed input signal pair comprising a first and a second transformed input signals; and for each transformed input signal pair, transmit the first transformed input signal to the input interface of the first resonator, and transmit the second transformed input signal to the input interface of the second resonator, thereby
• the present invention is an apparatus, comprising: a first superconducting electromagnetic resonator; a second superconducting electromagnetic resonator intersecting the first resonator, thereby defining an intersection area; a transmon capacitively tunably coupled to the first resonator and the second resonator; a microwave (MW) source operatively coupled to the transmon, the MW source configured to generate one or more drive signals; a transmon readout means operatively coupled to the transmon; and wherein the transmon is configured to: based on the one or more drive signal, be placed into a first quantum state, thereby generating an input signal; strengthen coupling to the first and the second resonators, and, based on the one or more drive signal, transmit the input signal into the first resonator and the second resonator, thereby generating a first resonator signal and the second resonator signal, wherein the first resonator signal and the second resonator signal have an
• the present invention is a method of determining an index of refraction of a sample, the method comprising: providing the apparatus of the fifth example embodiment, wherein the intersection area is adapted to receive the sample and evanescently couple thereto, the sample having a complex index of refraction defined by a real part and an imaginary part; disposing the sample at the intersection area; causing the MW source to generate one or more drive signals; causing the transmon to: based on the one or more drive signal, be placed in a first quantum state, thereby generating an input signal; strengthen coupling to the first and the second resonators, and, based on the one or more drive signal, transmit the input signal into the first resonator and the second resonator, thereby generating a first resonator signal and the second resonator signal, wherein the first resonator signal and the second resonator signal have an input amplitude ratio; reduce coupling to the first and the second resonators; based on
• FIG. 1A is a schematic view of a cross-cavity device according to embodiments of the present disclosure.
• Fig. IB is a level diagram illustrating spectrum of the two cavities according to embodiments of the present disclosure.
• FIG. 1C is a schematic view of an apparatus comprising the cross-cavity device according to embodiments of the present disclosure.
• Fig. ID is a schematic view of an additional embodiment of an apparatus comprising the cross-cavity device according to the present disclosure.
• Fig. 2A is a polar plot of a quantum metric according to embodiments of the present disclosure.
• the present invention is an apparatus.
• the apparatus comprises: a first electromagnetic resonator; a second electromagnetic resonator intersecting the first resonator, thereby defining an intersection area, the first and the second resonator each comprising at least one interface; a source configured to generate an electromagnetic source signal; at least a first detector; at least one input/ output means in electromagnetic communication with the source, the at least one interface of the first resonator and the at least one interface of the second resonator; and wherein the at least one input/output means is configured to: based on a source signal, generate a first input signal and a second input signal; apply to the first and the second signals an input amplitude ratio and an input relative phase shift, thereby generating a first transformed input signal and a second transformed input signal; transmit the first transformed input signal to the at least one interface of the first resonator, thereby generating a first output signal therefrom; and transmit the second transformed input signal to the at
• the apparatus further comprises a controller configured to: cause the source to generate the source signal; and based on the at least the first result signal, compute the real and the imaginary parts of the index of refraction of the sample.
• the optical source is a single photon source, and the first and second detectors are each a single photon detector. The remainder of the features and example features of the 1 st example embedment are as described above with respect to its various aspects.
• the optical source is a coherent photon source. The remainder of the features and example features of the 1 st example embedment are as described above with respect to its various aspects.
• the at least one input/output means comprises an adjustable beam splitter and at least one adjustable phase shifter.
• the remainder of the features and example features of the 1 st example embedment are as described above with respect to its various aspects.
• the first and the second optical resonators each comprises a Fabry-Perot cavity.
• the present invention is an apparatus.
• the apparatus comprises a first electromagnetic resonator; a second electromagnetic resonator intersecting the first resonator, thereby defining an intersection area, the first and the second resonator each comprising an input interface and an output interface; a source configured to generate an electromagnetic source signal; a first detector and a second detector; an input means in electromagnetic communication with the source, the input interface of the first resonator and the input interface of the second resonator; and an output means in electromagnetic communication with the output interface of the first resonator, the output interface of the second resonator, and the first and the second detectors, wherein the input means is configured to: based on a source signal, generate a first input signal and a second input signal; apply to the first and the second signals an input amplitude ratio and an input relative phase shift, thereby generating a first transformed input signal and a second transformed input signal; transmit the first transformed input signal to the input interface of the first reson
• the intersection area is adapted to receive a sample and evanescently couple thereto, the sample having a complex index of refraction defined by a real part and an imaginary part.
• the apparatus further comprises a controller configured to: cause the source to generate the source signal; and based on the first result signal and the second result signal, compute the real and the imaginary parts of the index of refraction of the sample.
• the input means and the output means each comprises an adjustable beam splitter and at least one adjustable phase shifter.
• the remainder of the features and example features of the 2 nd example embedment are as described above with respect to its various aspects.
• the present invention is a method of determining an index of refraction of a sample.
• the method comprises:
• intersection area is adapted to receive the sample and evanescently couple thereto, the sample having a complex index of refraction defined by a real part and an imaginary part;
• the at least one input/ output means to: based on the source signal, generate a plurality of input signal pairs, each input signal pair comprising a first and a second input signals; for each input signal pair, apply to the first and the second input signals an input amplitude ratio and an input relative phase shift, thereby generating a transformed input signal pair, the transformed input signal pair comprising a first and a second transformed input signals; and for each transformed input signal pair, transmit the first transformed input signal to the at least one interface of the first resonator, and transmit the second transformed input signal to the at least one interface of the second resonator, thereby generating an output signal pair, the output signal pair comprising a first and a second output signal;
• intersection area is adapted to receive the sample and evanescently couple thereto, the sample having a complex index of refraction defined by a real part and an imaginary part;
• the transmon is a tunable transmon.
• the apparatus further comprises a flux bias means operatively coupled to the transmon, the flux bias means configured to change a magnetic flux through the transmon, thereby adjusting the transmon frequency.
• the intersection area is adapted to receive a sample and evanescently couple thereto, the sample having a complex index of refraction defined by a real part and an imaginary part.
• the remainder of the features and example features of the 5 th example embedment are as described above with respect to its various aspects.
• the apparatus further comprises a controller configured to: cause the MW source to generate the one or more drive signals; and based on at least the first resonator signal, compute the real and the imaginary parts of the index of refraction of the sample.
• the present invention is a method of determining an index of refraction of a sample.
• the method comprises:
• the transmon to: based on the one or more drive signal, be placed in a first quantum state, thereby generating an input signal; strengthen coupling to the first and the second resonators, and, based on the one or more drive signal, transmit the input signal into the first resonator and the second resonator, thereby generating a first resonator signal and the second resonator signal, wherein the first resonator signal and the second resonator signal have an input amplitude ratio; reduce coupling to the first and the second resonators; based on the one or more drive signal, be placed in a second quantum state, thereby imparting a first relative phase shift to the first and the second resonator signals; based on the one or more drive signal, be placed in a third quantum state, thereby imparting a second relative phase shift to the first and the second resonator signals, wherein the second relative phase shift is a sign-reverse of the first relative phase shift; based on the one or more drive signal, be
• transmon readout means to read out at least the first resonator signal from the transmon
• a cross-cavity device in a planar geometry with a small dielectric sample at the intersection as shown in Fig. 1A.
• Fig. 1A illustrates a realization of the cross-cavity device 10 using rectangular resonators 12 fabricated on a substrate 16.
• a sample 14 is mounted at the intersection of the two resonators 12 and couples evanescently to the electric field modes.
• cr H is the Hall conductivity
• e lJ is the Levi-Civita tensor.
• the diagonal conductivity is set to zero and its effect is incorporated in the coherence time of the device.
• the cavities are characterized by a conductivity tensor cr 0 and a susceptibility tensor % 0 which define the “reference vacuum” for the electric field.
• each cavity can support a single mode with the electric field sufficiently permeating into free space such that it evanescently couples to the sample.
• the system quantum is treated mechanically in the case of closed dynamics, i.e., in the absence of any coupling to the environment; nonunitary process, e.g., losses, may be introduced by replacing the unitary evolution operator with a completely positive map.
• Fig. IB illustrates the spectrum 20 of two cavities with equispaced energy levels separated by the resonant frequency to x or a> y .
• the complex coupling g g x + ig a between the energy levels is determined by the off-diagonal components of the susceptibility tensor % and Hall conductivity a H .
• the energy levels in each Fock subspace are split according to the magnitude of 5, as shown in spectrum 20.
• the rea and imaginary g a upling between the modes arise due to an off-diagonal susceptibility x xy and finite Hall conductivity cr H , respectively.
• Equation (19) describes two bosonic oscillators with commutation relations and resonant frequenciesS x and S y . that interact via a complex coupling g. It can be readily recast into Eq. (2) by defining the elements of the SU(2) algebra as: with commutation relations
• Device 500 includes waveguides Rx (501) and R y (502).
• An ancilla transmon Q (503) is connected to waveguides 501, 502 and is used for loading Fock states in R(x/ y ).
• Flux bias 504 is used for tuning the frequency of transmon 503.
• RF ports 505, 506, 507 are used for direct readout and drive of the resonators 501, 502 and transmon 503.
• An exemplary protocol for measurement comprises: 1. State initialization; 2.
• a flux bias line 504 is used to move the frequency of the transmon into resonance with the cavity.
• Other techniques do not require a tunable transmon but have more complicated pulse sequences. Accordingly, a SWAP gate may be applied according to various alternative implementations.
• state initialization step provides a mechanism by which the transmon injects a photon into the cavity system, similar to a quantum emitter in optics.
• beamsplitting (Y g ) is implemented through an engineered time-dependent coupling between mode x and mode y.
• the transmon 503 is driven by two microwave pulses with amplitudes and frequencies respectively.
• the strength of the time-dependent interaction is determined by the dispersive coupling of the transmon to each mode of the resonator and the amplitudes of the pulses.

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• 2024
  • 2024-03-06 EP EP24877707.0A patent/EP4677318A2/de active Pending
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