Spectrometer including vertical stack structure and non-invasive biometric sensor including the spectrometer

A non-invasive biometric sensor comprising:

• a spectrometer configured to obtain a spectrum distribution of a scattered light, which is generated from an object by an excitation light;
• and
• a controller configured to control operations of the spectrometer and analyze properties of the object by using signals provided by the spectrometer,
• the spectrometer comprising:
• a stacked light absorbing structure comprising a plurality of absorbing layers stacked in a vertical direction and having a plurality of absorption wavelength bands, and a plurality of tunnel junction layers respectively interposed between the plurality of absorbing layers to electrically connect the plurality of absorbing layers;
• a light source configured to generate an illumination light including the plurality of absorption wavelength bands of the plurality of absorbing layers;
• and
• a notch filter array disposed between the light source and the stacked light absorbing structure and comprising a plurality of notch filters having a plurality of absorption characteristics to block only a wavelength band selected from among the plurality of absorption wavelength bands,
• wherein the controller is configured to control the notch filter array to rotate according to a lapse of time to change, in a sequential order, the selected wavelength band to be blocked among the plurality of absorption wavelength bands.

A non-invasive biometric sensing method comprising:

• radiating an excitation light to an object;
• providing a scattered light, which is generated from the object by the excitation light, to a stacked light absorbing structure, the stacked light absorbing structure comprising first to Nth absorbing layers stacked in a vertical direction and having different first to Nth absorption wavelength bands, and a plurality of tunnel junction layers respectively interposed between the first to Nth absorbing layers to electrically connect the first to Nth absorbing layers;
• providing the stacked light absorbing structure with an illumination light for saturation of the second to Nth absorbing layers, other than the first absorbing layer, together with the providing of the scattered light, by using a notch filter array to block only the first absorption wavelength band selected from among the first to Nth absorption wavelength bands;
• obtaining a first photocurrent generated by the stacked light absorbing structure;
• calculating a light amount of a first wavelength band component in the scattered light by using the obtained first photocurrent;
• and
• repeating a photocurrent obtaining operation to calculate light amounts of a second wavelength band component to an Nth wavelength band component in the scattered light, by controlling the notch filter array to rotate according to a lapse of time to change, in a sequential order, an absorption wavelength band to be blocked selected from among the first to Nth absorption wavelength bands.

A biological signal sensor comprising:

• a stacked light absorbing structure comprising a plurality of light absorption layers configured to receive a light that saturates the plurality of light absorption layers excluding one of the plurality of light absorption layers and receive a bio-optical signal that activates the excluded light absorption layer, each of the plurality of light absorption layers being configured to absorb a different wavelength band of an optical spectrum;
• a light source configured to generate an illumination light including a plurality of absorption wavelength bands of the plurality of light absorption layers;
• a notch filter array disposed between the light source and the stacked light absorbing structure and comprising a plurality of notch filters having a plurality of absorption characteristics to block only a wavelength band selected from among the plurality of absorption wavelength bands;
• and
• a controller configured to control the notch filter array to rotate according to a lapse of time to change, in a sequential order, the selected wavelength band to be blocked among the plurality of absorption wavelength bands, and obtain a photocurrent generated from the stacked light absorbing structure and analyze the bio-optical signal based on the obtained photocurrent.