Apertureless spectrometer

1. A hard-apertureless spectrometer comprising:

a light source configured to provide excitation light to a target to form a focal point on the target such that a soft-aperture which is a virtual aperture corresponding to the focal point of the target is formed on the target;

a spatial filter located on an optical path through which the excitation light reaches the target from the light source;

a housing including a hole through which light provided from the soft-aperture on the target enters;

a collimator configured to collimate the light provided from the soft-aperture of the target;

a diffraction grating configured to spectroscopically analyze the collimated light;

a condenser configured to condense the spectroscopically analyzed light; and

a photodetector configured to receive the condensed light output from the condenser and detect a target characteristic;

wherein a size of the soft-aperture is determined by a size of the focal point of the excitation light, and a shape of the soft-aperture is determined by the spatial filter.

2. The hard-apertureless spectrometer of claim 1 , wherein the light source is located outside the hard-apertureless spectrometer.

3. The hard-apertureless spectrometer of claim 1 , wherein the collimator, the diffraction grating, the condenser, and the photodetector are housed in the housing.

4. The hard-apertureless spectrometer of claim 1 , wherein the collimator is located outside the housing.

5. The hard-apertureless spectrometer of claim 1 , further comprising a beam delivery device which is configured to provide the light provided from the soft-aperture of the target to the collimator and includes a plurality of lenses or mirrors.

6. The hard-apertureless spectrometer of claim 1 , wherein:

the light source is located inside the hard-apertureless spectrometer;

the hard-apertureless spectrometer further includes a dichroic mirror; and

the excitation light provided from the light source is provided to the target through any one of a dichroic mirror and a beam splitter to form the soft-aperture.

7. The hard-apertureless spectrometer of claim 1 , wherein:

one or more filters among a tube bellow, a band pass filter, a long pass filter, and a short pass filter are further disposed in the hole; or

the collimator is coated with a filter material.

8. A hard-apertureless Raman spectrometer comprising:

a light source configured to provide excitation light to a target to form a focal point on the target such that a soft-aperture which is a virtual aperture corresponding to the focal point of the target is formed on the target;

a spatial filter located on an optical path through which the excitation light reaches the target from the light source;

a housing including a hole through which light provided from the soft-aperture on the target enters;

a collimator configured to collimate Raman light formed by providing the excitation light to the soft-aperture of the target;

a diffraction grating configured to spectroscopically analyze the Raman light;

a condenser configured to condense the spectroscopically analyzed Raman light; and

a photodetector configured to receive the condensed light output from the condenser and detect a target characteristic,

wherein a size of the soft-aperture is determined by a size of the focal point of the excitation light, and a shape of the soft-aperture is determined by the spatial filter.

9. The hard-apertureless Raman spectrometer of claim 8 , wherein the light source is located outside the hard-apertureless Raman spectrometer.

10. The hard-apertureless Raman spectrometer of claim 8 , wherein the collimator, the diffraction grating, the condenser, and the photodetector are housed in the housing.

11. The hard-apertureless Raman spectrometer of claim 8 , wherein the collimator is located outside the housing.

12. The hard-apertureless Raman spectrometer of claim 8 , further comprising a beam delivery device which is configured to provide the light provided from the soft-aperture of the target to the collimator and includes a plurality of lenses or mirrors.

13. The hard-apertureless Raman spectrometer of claim 8 , wherein:

the light source is located inside the hard-apertureless Raman spectrometer;

the Raman spectrometer further includes any one of a dichroic mirror and a beam splitter; and

the excitation light provided from the light source is provided to the target through any one of the dichroic mirror and the beam splitter to form the soft-aperture.

14. The hard-apertureless Raman spectrometer of claim 8 , further comprising one or more filters among a band pass filter, a long pass filter, and a short pass filter, which selectively filter only Raman light.

15. The hard-apertureless Raman spectrometer of claim 8 , wherein:

one or more filters among a tube bellow, a band pass filter, a long pass filter, and a short pass filter are further disposed in the hole; or

the collimator is coated with a filter material.