Multistage semiconductor quantum detector circuit incorporating anticorrelation
A novel and useful multistage semiconductor quantum detector circuit incorporating an anticorrelation mechanism. The quantum structure has at least the first stage sensor of the detector merged into the quantum structure in order to minimize loading of the quantum structure. The merged quantum structure and detector sensor may be encapsulated in a metal cage in order to provide enhanced rejection of the environmental parasitic electric and/or magnetic fields. A double boot strapping detector front-end configuration substantially eliminates the loading coming from both the gate-source and the gate-drain parasitic capacitances of the first sensor device of the detector that is connected to the quantum structure. In addition, differential detection aids in rejecting leakage, noise, and correlated interference coupling. Both dummy referenced differential detection as well as self-referenced differential detection may be employed in the detector. Moreover, correlated double sampling is used after preamplification in the detector in order to further reject noise and perturbations in the system.
1. A quantum detector coupled to a quantum circuit, comprising:
a main quantum sensor coupled to a main semiconductor quantum well whose output is to be detected for a presence or absence of a particle previously injected thereto, said main quantum sensor operative to generate a main sensor signal;
a dummy quantum sensor coupled to a dummy semiconductor quantum well whereby no particle is injected thereto, said dummy quantum sensor operative to generate a dummy sensor signal; and
an amplifier and conditioning circuit operative to detect the presence or absence of said particle at the output of said main quantum circuit in accordance with a difference between said main sensor signal and said dummy sensor signal.
2. The quantum detector according to claim 1 , wherein said main quantum sensor and said dummy quantum sensor each comprise at least one source follower device.
3. The quantum detector according to claim 1 , wherein said an amplifier and conditioning circuit comprises a differential amplifier whose inputs comprise said main sensor signal and said dummy sensor signal and is operative to cancel out common mode noise.
4. The quantum detector according to claim 1 , further comprising a device exclusion zone between said main quantum sensor, said dummy quantum sensor and said amplifier and conditioning circuit, said device exclusion zone operative to isolate said main semiconductor quantum well and associated quantum circuit from noise generated by surrounding classical semiconductor devices.
5. The quantum detector according to claim 1 , wherein said main quantum sensor, said dummy quantum sensor and said amplifier and conditioning circuit comprise classical semiconductor circuitry.
6. A quantum detector coupled to a quantum circuit, comprising:
a main quantum sensor coupled to a first end of a semiconductor quantum well and operative to generate a main sensor signal corresponding to the presence or absence at said first end of a particle previously injected into said semiconductor quantum circuit;
a complementary quantum sensor coupled to a second end of the semiconductor quantum well and operative to generate a complementary sensor signal corresponding to the presence or absence of the particle at said second end; and
an amplifier and conditioning circuit operative to detect the presence or absence of said particle in said semiconductor quantum well in accordance with a self-referenced difference between said main sensor signal and said complementary sensor signal.
7. The quantum detector according to claim 6 , wherein said main quantum sensor and said complementary quantum sensor each comprise at least one source follower device.
8. The quantum detector according to claim 6 , wherein said an amplifier and conditioning circuit comprises a differential amplifier whose inputs comprise said main sensor signal and said complementary sensor signal and is operative to cancel out common mode noise.
9. The quantum detector according to claim 6 , further comprising a device exclusion zone between said main quantum sensor, said complementary quantum sensor and said amplifier and conditioning circuit, said device exclusion zone operative to isolate said semiconductor quantum well and associated quantum circuit from noise generated by surrounding classical semiconductor devices.
10. The quantum detector according to claim 6 , wherein said main quantum sensor, said complementary quantum sensor and said amplifier and conditioning circuit comprise classical semiconductor circuitry.
11. A quantum detector, comprising:
a sensor coupled to a quantum well of a semiconductor quantum circuit and operative to generate a sensor signal corresponding to the presence or absence of a particle previously injected into said semiconductor quantum circuit;
an amplifier and conditioning circuit operative to receive an output of said sensor, said amplifier and conditioning circuit comprising:
a preamplifier circuit operative to convert presence of charge at its input to a voltage signal;
a correlated double sampler (CDS) circuit coupled to said preamplifier and operative to further reject noise from said voltage signal;
a post-amplifier circuit coupled to said CDS and operative to generate a detection output signal from an output of said CDS; and
a device exclusion zone surrounding said quantum circuit and sensor and operative to isolate said quantum circuit and sensor from said amplifier and conditioning circuit.
12. The quantum detector according to claim 11 , further comprising a metal cage encapsulating said quantum circuit and said sensor.
13. The quantum detector according to claim 11 , wherein said sensor comprises at least one source follower device.
14. The quantum detector according to claim 11 , wherein said CDS comprises circuitry operative to sample said voltage signal before and after said particle is transferred to a last qdot in said quantum circuit to generate a first voltage and a second voltage, wherein a difference signal between said first voltage and said second voltage is generated indicative of the presence or absence of said particle at said sensor.
15. The quantum detector according to claim 11 , wherein said sensor and said amplifier and conditioning circuit comprise classical semiconductor circuitry.
16. A method of detecting a presence or absence of a particle in a main quantum circuit, comprising:
first sensing via a first sensor for the presence or absence of a particle previously injected into a main quantum circuit and generating a main sensor signal thereby;
second sensing via a second sensor an absence of a particle in a dummy quantum circuit and generating a dummy sensor signal thereby; and
generating a detector output in accordance with a difference signal corresponding to a difference between said main sensor signal and said dummy sensor signal.
17. The method according to claim 16 , further comprising sampling said difference signal before and after said particle is transferred to a last qdot in said quantum circuit to generate a first difference signal and a second difference signal, wherein a third difference signal between said first difference signal and said second difference signal is generated indicative of the presence or absence of said particle at said first sensor.
18. The method according to claim 16 , further comprising providing an isolating device exclusion zone between said first sensor, said second sensor, said quantum circuit and an amplifier and conditioning circuit that is operative to generate said detector output.
19. A method of detecting a presence or absence of a particle in a main quantum circuit, comprising:
first sensing via a first sensor at one end of a quantum circuit for the presence or absence of a particle previously injected therein and generating a first sensor signal thereby;
second sensing via a second complementary sensor at a second end of the quantum circuit for the presence or absence of a particle and generating a complementary second sensor signal thereby; and
generating a detector output in accordance with a difference signal corresponding to a difference between said first sensor signal and said complementary second sensor signal.
20. The method according to claim 19 , further comprising sampling said difference signal before and after said particle is transferred to a last qdot in said quantum circuit to generate a first difference signal and a second difference signal, wherein a third difference signal between said first difference signal and said second difference signal is generated indicative of the presence or absence of said particle at said first sensor.
21. The method according to claim 19 , further comprising providing an isolating device exclusion zone between said first sensor, said second complementary sensor, said quantum circuit and an amplifier and conditioning circuit that is operative to generate said detector output.