CN111649821B

CN111649821B - Implementation method of superconducting nanowire single-pixel spectrometer with programmable responsivity

Info

Publication number: CN111649821B
Application number: CN202010504790.2A
Authority: CN
Inventors: 赵清源; 孔令东
Original assignee: Nanjing University
Current assignee: Nanjing University
Priority date: 2020-06-05
Filing date: 2020-06-05
Publication date: 2021-07-30
Anticipated expiration: 2040-06-05
Also published as: CN111649821A

Abstract

The invention discloses a realization method of a superconducting nanowire single-pixel spectrometer with programmable responsivity, which comprises the steps of measuring an intrinsic wavelength-current response matrix of a superconducting nanowire single-photon detector, measuring the light counting rate under different currents and calculating and reconstructing; the method comprises the following steps: the first step is as follows: calibrating an eigenwavelength-current response matrix phi (i, lambda) of the superconducting nanowire single photon detector; the second step is that: measuring the light counting rate y (i) under different currents under the irradiation of incident light; the third step: and calculating and reconstructing an incident spectrum x (lambda). By adopting the method for realizing the programmable responsivity superconducting nanowire single-pixel spectrometer, the spectrum measurement under extremely weak light can be realized by only one detection unit without an additional optical modulation unit and a detector array.

Description

Implementation method of superconducting nanowire single-pixel spectrometer with programmable responsivity

Technical Field

The invention relates to an integrated miniature single-pixel spectrometer, in particular to a superconductive nanowire single-pixel spectrometer with programmable responsivity, which is suitable for spatial compact spectrum detection under extremely weak light.

Background

For spectral detection under extremely weak light, a detector with single photon sensitivity is required. The superconducting nanowire single photon detector has many excellent performances: wide spectral response range, low dark count, high dynamic range and ease of on-chip photonic integration. Although the superconducting nanowire single photon detector has a wide spectral response range, the superconducting nanowire single photon detector does not have spectral resolution capability, and a spectrometer is manufactured, an additional optical element is arranged in front of the detector in the current method, so that the superconducting nanowire single photon detector is large in size and cannot meet the requirements of compact applications.

Disclosure of Invention

In view of the above-mentioned problems and deficiencies of the prior art, it is an object of the present invention to provide a superconducting nanowire single-pixel spectrometer with programmable responsivity.

The invention adopts the following technical scheme:

the implementation method of the superconducting nanowire single-pixel spectrometer with programmable responsivity comprises the steps of measuring an intrinsic wavelength-current response matrix of a superconducting nanowire single-photon detector, measuring the light counting rate under different currents and calculating and reconstructing; the method comprises the following steps:

the first step is as follows: calibrating an eigenwavelength-current response matrix phi (i, lambda) of the superconducting nanowire single photon detector;

the second step is that: measuring the light counting rate y (i) under different currents under the irradiation of incident light;

the third step: and calculating and reconstructing an incident spectrum x (lambda).

Further, in the first step, the detector is biased at different currents, and the photon count rates at unit power of the light radiation with different wavelengths are measured to obtain a spectral response matrix Φ (i, λ) which is a function of the wavelength of the incident light and the bias current of the detector, and each row of the matrix represents the spectral response rate at different currents, and each column represents the change of the count rate at different wavelengths with the bias current.

Further, in the second step, after the response matrix is calibrated, the spectrum x (λ) of the incident light is measured, as long as the light counting rates y (i) at different currents are measured, and the measurement process is described as the following linear equation set:

Φx＝y#(1)。

further, in the third step, x is obtained by solving a linear equation set (1).

Further, the solution of the system of linear equations (1) utilizes a linear regression method:

further, in step one, the calibration wavelength-bias current response matrix is the property of the detector itself, and is independent of the external light source.

The invention has the following beneficial effects:

by adopting the method for realizing the programmable responsivity superconducting nanowire single-pixel spectrometer, the spectrum measurement under extremely weak light can be realized by only one detection unit without an additional optical modulation unit and a detector array. The method of the present invention enables a completely new single-pixel spectrometer, which is distinguished from existing spectrometers, without additional optical modulation units or detector arrays, the entire spectrometer containing only one detector (hence the name single-pixel spectrometer).

Drawings

FIG. 1 is a graph of a measured wavelength-offset response matrix of the present invention;

FIG. 2 is a schematic diagram of the working mechanism of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

The superconducting nanowire single photon detector is a photon counting type detector, and measured light intensity can be represented by the counting rate of the detector. It consists of superconducting thin film nanowires biased by current, as shown in part a of fig. 2. When a photon is absorbed by the nanowire, an electrical pulse is probabilistically generated. This probability and the magnitude of the bias current are related to the energy of the photons. When the bias current is increased, the cutoff wavelength of the detector response shifts to longer wavelengths, as shown in section b of FIG. 1. That is to say, when the bias is at different currents, the spectral responsivity of the detector is linearly independent, namely the invention finds that the superconducting nanowire single photon detector has the characteristic that the spectral responsivity is different when the bias is at different currents, and the invention utilizes the characteristic of the superconducting nanowire single photon detector.

The realization method of the superconducting nanowire single-pixel spectrometer with programmable responsivity is used for measuring the wavelength-current response matrix of the superconducting nanowire, measuring the light counting rate under different currents and calculating and reconstructing. The operation mechanism of the invention is divided into three steps:

the first step is as follows: and calibrating a wavelength-current response matrix of the superconducting nanowire single photon detector. This is done by biasing the detector at different currents and measuring the photon count rates per unit power of the light radiation at different wavelengths to obtain a spectral response matrix phi (i, lambda), as shown in part a of fig. 1. This matrix is a function of the wavelength of the incident light and the detector bias current, with each row representing the spectral responsivity at a different current and each column representing the count rate as a function of bias current at a different wavelength. It should be noted that, in the present invention, the calibration wavelength-bias current response matrix is the nature of the detector itself, and is independent of the external light source.

The second step is that: when the response matrix is calibrated, the spectrum x (λ) of the incident light is measured by measuring the light counting rate y (i) at different currents, as shown in part b of fig. 2, and this measurement process can be mathematically described as the following linear equation set:

Φx＝y#(1)

the third step: and calculating and reconstructing an incident spectrum. This step is to solve the system of linear equations (1) to obtain x. In general, the solution of this system of linear equations can utilize a linear regression method:

in summary, the present invention finds and utilizes a wavelength-current response matrix intrinsic to the detector, thereby realizing a spectrometer that requires only one detector without additional optical elements or light sources.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The realization method of the superconducting nanowire single-pixel spectrometer with programmable responsivity is characterized by comprising the following steps: measuring an intrinsic wavelength-current response matrix of the superconducting nanowire single photon detector, measuring the light counting rate under different currents and calculating and reconstructing; the method comprises the following steps:

biasing the detector at different currents and measuring the count rates of photons at unit power radiated by light of different wavelengths to obtain a spectral response matrix Φ (i, λ) as a function of wavelength of the incident light and bias current of the detector, each row of which represents the spectral response rate at different currents and each column represents the change in count rate at different wavelengths with bias current; when the bias current is increased, the cut-off wavelength of the detector response is shifted to longer wavelength, and the spectral responsivity of the superconducting nanowire single photon detector under bias of different currents is different;

2. The realization method of the programmable responsivity superconducting nanowire single-pixel spectrometer of claim 1, characterized in that: in the second step, after the response matrix is calibrated, the spectrum x (λ) of the incident light is measured, as long as the light counting rate y (i) under different currents is measured, and the measurement process is described as the following linear equation set:

Φx＝y#(1)。

3. the realization method of the programmable responsivity superconducting nanowire single-pixel spectrometer of claim 2, characterized in that: and step three, solving a linear equation set (1) to obtain x.

4. The method for realizing the programmable responsivity superconducting nanowire single-pixel spectrometer as claimed in claim 3, wherein the method comprises the following steps: the solution of the system of linear equations (1) utilizes a linear regression method:

5. the realization method of the programmable responsivity superconducting nanowire single-pixel spectrometer of claim 1, characterized in that: in the first step, the calibration wavelength-bias current response matrix is the property of the detector and is independent of an external light source.