Circularly polarized light illuminator, analysis device, and microscope

Abstract

A circularly polarized light irradiator capable of high-speed and high-sensitivity circular dichroism measurement is provided, as well as an analytical apparatus and microscope using the circularly polarized light irradiator. The analytical apparatus and microscope using the circularly polarized light irradiator include: a light source (20) that emits pulsed light; a polarization separation unit that separates the pulsed light (L1) emitted from the light source (20) or linearly polarized light (L2) extracted from the pulsed light (L1) emitted from the light source (20) into an x-axis polarized light component (L2x) and a y-axis polarized light component (L2y); and a light delay unit (13) that delays the pulsed light of the separated x-axis polarized light component. The pulses (Px) and (Py) of the y-axis polarized light components are delayed relative to the other; the polarization light combining unit coaxially combines the X-polarized pulse beam (L2x) and the Y-polarized pulse beam (L2y) emitted from the light delay unit (13) to generate a linearly polarized beam (L3) with alternating repeating X-polarized light pulses (Px) and Y-polarized light pulses (Py); and the polarization light conversion unit converts the linearly polarized light emitted from the polarization light combining unit into circularly polarized light.

Claims

1. A circularly polarized light illuminator, wherein, This circularly polarized light illuminator has the following features: A light source that emits pulsed light; The polarization separation unit separates the pulse light emitted from the light source into an x-axis polarized light component and a y-axis polarized light component; An optical delay section delays either the pulse of the x-axis polarized light component or the pulse of the y-axis polarized light component obtained by the polarization separation section relative to the other. The polarization beam combining unit coaxially combines a pulse beam consisting of an x-axis polarized light component and a pulse beam consisting of a y-axis polarized light component emitted from the optical delay unit to generate a modulated linearly polarized pulse beam in which pulses with x-axis polarized light components and pulses with y-axis polarized light components repeat alternately. as well as The polarization conversion unit converts linearly polarized light emitted from the polarization combining unit into circularly polarized light.

2. The circularly polarized light irradiator according to claim 1, wherein, A modulated circularly polarized pulse beam, consisting of alternating right-circularly polarized pulses and left-circularly polarized pulses, is emitted from the polarization conversion unit.

3. The circularly polarized light irradiator according to claim 1, wherein, The optical delay section makes the optical path length of either the x-axis component or the y-axis component of the incident linearly polarized light longer than the optical path length of the other.

4. The circularly polarized light irradiator according to claim 3, wherein, The optical delay section is provided with an extended optical path consisting of a right-angle prism reflector and a rear reflector.

5. The circularly polarized light irradiator according to claim 1, wherein, The optical delay unit sets the delay time by emitting a pulse of the delayed component between one pulse of the undelayed component and the next pulse.

6. The circularly polarized light irradiator according to claim 1, wherein, The polarization separation unit includes an optical element that shifts or changes the angle of the optical axis of either the x-axis polarized light component or the y-axis polarized light component relative to the incident optical axis.

7. An analytical apparatus, wherein, The analytical apparatus includes the circularly polarized light irradiator as described in any one of claims 1 to 6. The analytical apparatus is used to irradiate a sample with circularly polarized light emitted from the circularly polarized light irradiator, thereby determining the optical properties of the sample.

8. The analytical apparatus according to claim 7, wherein, The analytical device has one or more photodetectors that detect transmitted light, reflected light, scattered light or emitted light from the sample as electrical signals.

9. The analytical apparatus according to claim 8, wherein, The analysis device includes a circular dichroism detection unit that obtains a circular dichroism signal based on an electrical signal detected by the photodetector.

10. The analytical apparatus according to claim 9, wherein, In the circular dichroism detection unit, the electrical signal of the transmitted light detected by the photodetector is locked and detected at the repetition frequency f of the pulse beam emitted from the light source, and the relative intensity difference between the left and right circularly polarized light in the transmitted light is calculated to obtain the circular dichroism signal.

11. The analytical apparatus according to claim 9, wherein, In the circular dichroism detection unit, the responses to the right-circularly polarized light pulse and the left-circularly polarized light pulse of the transmitted light detected by the photodetector are integrated separately, and the signal intensity when the right-circularly polarized light pulse has been irradiated and the signal intensity when the left-circularly polarized light pulse has been irradiated are calculated independently. The circular dichroism signal is calculated based on their intensity difference.

12. A microscope, wherein, The microscope is equipped with a circularly polarized light illuminator as described in any one of claims 1 to 6. The microscope is used to irradiate a sample of the object of observation with circularly polarized light emitted from the circularly polarized light irradiator.

13. The microscope according to claim 12, wherein, The microscope has the following features: Objective lens, used to capture transmitted light from the sample; An imaging lens that images the transmitted light emitted from the objective lens; A photodetector that detects the transmitted light as an electrical signal; as well as The circular dichroism detection unit obtains the circular dichroism signal based on the electrical signal detected by the photodetector.

14. The microscope according to claim 13, wherein, In the circular dichroism detection unit, the electrical signal of the transmitted light detected by the photodetector is locked and detected at the repetition frequency f of the pulse beam emitted from the light source, and the relative intensity difference between the left and right circularly polarized light in the transmitted light is calculated to obtain the circular dichroism signal.

15. The microscope according to claim 13, wherein, In the circular dichroism detection unit, the responses to the right-circularly polarized light pulse and the left-circularly polarized light pulse of the transmitted light detected by the photodetector are integrated separately, and the signal intensity when the right-circularly polarized light pulse has been irradiated and the signal intensity when the left-circularly polarized light pulse has been irradiated are calculated independently. The circular dichroism signal is calculated based on their intensity difference.

16. The microscope according to claim 13, wherein, The core of an optical fiber is disposed at the imaging position of the transmitted light, and a portion of the image of the transmitted light is extracted by the optical fiber and transmitted to the photodetector.

Images