Ever since the invention of the microscope, humanity has gained access to the world of the incredibly small. Scientists discovered that creatures never known to exist before are alive in an uncountable number in spaces as small as the head of a pin. But the microscope unlocked some interesting forms of art as well. Not only could people view and photograph small objects with them, but in the mid-nineteenth century, various artists and scientists used them to shrink photographs themselves down into the world of the microscopic. This article goes into depth on how one man from this era invented the art form known as microphotography.

Compared to photomicroscopy, which uses a microscope or other similar optical device to take normal-sized photographs of incredibly small things, microphotography takes the reverse approach of taking pictures of normal-sized things and shrinking them down to small sizes. [John Benjamin Dancer] was the inventor of this method, which used optics to shrink an image to a small size. The pictures were developed onto photosensitive media just like normal-sized photographs. Not only were these unique pieces of art, which developed — no pun intended — into a large fad, but they also had plenty of other uses as well. For example, since the photographs weren’t at all obvious without a microscope, they found plenty of uses in espionage and erotica.

Although the uses for microphotography have declined in today’s digital world, there are still plenty of unique pieces of art around with these minuscule photographs, as well as a bustling collector culture around preserving some of the antique and historical microphotographs from before the turn of the century. There is also similar technology, like microfilm and microfiche, that were generally used to preserve data instead of creating art, although plenty of these are being converted to digital information storage now.

Taking a picture with a single photoresistor is a brain-breaking idea. But go deeper and imagine taking that same picture with the same photoresistor, but without even facing the object. [Jon Bumstead] did exactly that with compressed sensing and a projector. Incredibly, the resulting image is from the perspective of the projector, not the “camera”.

This camera setup is very similar to one we’ve seen before, but far more capable. The only required electronics are a small projector and a single photodiode. The secret sauce in this particular design lies in the pattern projected and the algorithm to parse the data.

Video is projected onto the target in the form of sinusoidal waves. As these waves change and move their way across the object, the sensor picks up whatever intensity value is reflected. Putting all this data together allows us to create a measured Fourier transform. Use the inverse Fourier transform, and BOOM, you got yourself an image. Better yet, you can even take a picture indirectly. Anything becomes a mirror — even paper — when all you rely on is the average relative intensity of light. If you want to take pictures like this on your own, check out [Jon]’s Instructable.

The science behind this technique is similar to the math that powers CT scanners and VAM 3D printing.

Thanks, [MrSVCD], for the tip!

We haven’t seen any projects from serial experimenter [Les Wright] for quite a while, and honestly, we were getting a little worried about that. Turns out we needn’t have fretted, as [Les] was deep into this exploration of the Pockels Effect, with pretty cool results.

If you’ll recall, [Les]’s last appearance on these pages concerned the automated creation of huge, perfect crystals of KDP, or potassium dihydrogen phosphate. KDP crystals have many interesting properties, but the focus here is on their ability to modulate light when an electrical charge is applied to the crystal. That’s the Pockels Effect, and while there are commercially available Pockels cells available for use mainly as optical switches, where’s the sport in buying when you can build?

As with most of [Les]’s projects, there are hacks galore here, but the hackiest is probably the homemade diamond wire saw. The fragile KDP crystals need to be cut before use, and rather than risk his beauties to a bandsaw or angle grinder, [Les] threw together a rig using a stepper motor and some cheap diamond-encrusted wire. The motor moves the diamond wire up and down while a weight forces the crystal against it on a moving sled. Brilliant!

The cut crystals are then polished before being mounted between conductive ITO glass and connected to a high-voltage supply. The video below shows the beautiful polarization changes induced by the electric field, as well as demonstrating how well the Pockels cell acts as an optical switch. It’s kind of neat to see a clear crystal completely block a laser just by flipping a switch.

Nice work, [Les], and great to have you back.

It’s sometimes easy to forget that the light in the sky is an actual star. With how reliable it is and how busy we tend to be as humans, we can take that incredible fact and stow it away and largely go on with our lives unaffected. But our star is the thing that gives everything on the planet life and energy and is important to understand. Humans don’t have a full understanding of it either; there are several unsolved mysteries in physics which revolve around the sun, the most famous of which is the coronal heating problem. To help further our understanding a number of scientific instruments have been devised to probe deeper into it, and this adaptive optics system just captures some of the most impressive images of it yet.

Adaptive optics systems are installed in terrestrial telescopes to help mitigate the distortion of incoming light caused by Earth’s atmosphere. They generally involve using a reference source to measure these distortions, and then make changes to the way the telescope gathers light, in this case by making rapid, slight changes to the telescope’s mirror. This system has been installed on the Goode Solar Telescope in California and has allowed scientists to view various solar phenomena with unprecedented clarity.

The adaptive optics system here has allowed researchers to improve the resolution from the 1000 km resolution of other solar telescopes down to nearly the theoretical limit of this telescope—63 km. With this kind of resolution the researchers hope that this clarity will help shine some light on some of the sun’s ongoing mysteries. Adaptive optics systems like this aren’t just used on terrestrial telescopes, either. This demonstration shows how the adaptive optics system works on the James Webb Space Telescope.

Thanks to [iliis] for the tip!