Preparing a structured optical beam for human observation

1. An optics method comprising:

processing an optical beam to produce a structured optical beam for human perception of optical polarization, wherein processing the optical beam comprises:

receiving the optical beam from a laser source;

attenuating the optical beam to an exposure irradiance level that is safe for direct viewing by a human eye of a subject;

expanding the optical beam to a size configured for a field of view of the human eye; and

preparing the optical beam with a position-dependent polarization profile;

illuminating the field of view of the human eye with the structured optical beam by directing the structured optical beam towards the human eye, wherein the structured optical beam comprises the position-dependent polarization profile, and illuminating the field of view of the human eye with the structured optical beam induces an entoptic profile that allows the human subject to perceive the position-dependent polarization profile.

2. The method of claim 1 , wherein receiving the optical beam from the laser source comprises receiving a blue optical beam with a mean wavelength between 450 and 470 nanometers.

3. The method of claim 2 , wherein attenuating the optical beam comprises attenuating the optical beam to the exposure irradiance level less than 10 −4 W m −2 .

4. The method of claim 1 , wherein expanding the optical beam comprises expanding the optical beam to a size configured to cover at least 3 degrees of the field of view of the human eye.

5. The method of claim 1 , wherein processing the optical beam comprises removing speckle patterns in the structured optical beam.

6. The method of claim 5 , wherein removing the speckle patterns comprises at least one of:

passing the optical beam through an optical element with a vibrating motion in a direction perpendicular to a propagation direction of the optical beam;

receiving the optical beam from a laser source having a broad wavelength distribution; or

introducing the optical beam to a diffusing element.

7. The method of claim 1 , wherein directing the structured optical beam comprises passing the structured optical beam through lenses to focus the structured optical beam onto the retina of the human eye.

8. The method of claim 1 , wherein expanding the optical beam comprises passing the optical beam through one or more lenses.

9. The method of claim 1 , wherein processing the optical beam comprises transmitting the optical beam through a single mode fiber from the attenuator to a collimating lens.

10. The method of claim 1 , wherein processing the optical beam comprises:

after attenuating the optical beam, expanding the optical beam to the size configured for the field of view of the human eye; and

after preparing the optical beam with the position-dependent polarization profile, removing speckle patterns in the structured optical beam.

11. The method of claim 1 , wherein preparing the optical beam with the position-dependent polarization profile comprises passing the optical beam through an interferometer.

12. The method of claim 1 , further comprising:

after directing the structured optical beam, receiving feedback from the subject in response to the induced entoptic profile; and

providing the feedback from the subject for analysis of the human eye of the subject.