Impressive, but I doubt even FRL can overcome this design limitations.
Digilens tried to do that since forever, and when you introduce more colors you will face the same kind of problems seen in Hololens 2.
“Finally, holographic lenses can be constructed so that the lens pro- files can be independently controlled for each of the three color primaries, giving more degrees of freedom than refractive designs. When used with the requisite laser illumination, the displays also have a very large color gamut.”
They have full colour working, and apparently well, in the benchtop prototype.
There’s discussion towards the end as to options for implementing full colour in the HMD prototype.
Would you mind elaborating on (or provide a link to) some of the problems you mentioned Hololens 2 having? Also, I've never heard of Digilens; do you have a preferred source for learning more about that device and what its limitations are?
Can you expand on what you mean by "more colors" ? Toward the end of the article they show a multi-color image from the larger benchtop version of the prototype. Do you mean that adding colors doesn't scale down beyond a certain size?
To be completely honest, I would settle for an early monochrome version - I'm sure people can still make some great games/features like this. I think the form factor (and hopefully price) really is so much more important at this point.