• Laser telemetry for vision correction: a complete operation with comments (not for the faint of heart)

    • Translation
    Now I will show what doctors usually never show to patients. More precisely, it shows everything in the form of a beautiful render, from which it does not follow at all that a piece of metal will stick up in your cornea for a couple of minutes. Fortunately, you will not feel this because of the anesthetic premedication, you will not know and do not remember, because the piece of iron will be out of focus.



    So, watch the video, and I will show the frames with comments. This is a real operation on a patient in a German clinic, the recording was made on a device like the “black box” of the VisuMAX device. In this case, the patient has agreed to use the recording for training purposes, usually access to such records is strictly limited.
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  • Laser that cuts inside the cornea: ReLEx procedure at the physical level

    • Translation
    The idea — to take and cut a lens in a transparent cornea — is not new. At first it was done manually, with a scalpel directly on the surface (difficult and very rough, with a sea of side effects). The first laser was used in 1979, then it was a pulsed infrared emitter with an effective pulse length of 4 nanoseconds.


    Step 1: creating a plasma bubble, in fact — a microburst. Step 2: expansion of the shock and heat waves. Step 3: cavitation bubble (plasma expansion). Step 4: the formation of a parallel slice at the expense of several adjacent laser focus points.

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  • Working with light: Starting your career at ITMO University

      One of our previous articles featured an overview of our photonics department students’ work lives. Today we’re going to expand on this topic by looking at four related MA programs: “Light Guide Photonics and Programmable Electronics”, “LED technologies and optoelectronics”, “Photonic materials” and “Laser technologies”. We sat down with some of the folks currently enrolled in these programs, as well as recent graduates, to talk about the role ITMO University played in kickstarting their careers.

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    • The wave method of building color scheme

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        In life we often face the challenge of choosing the right colors. This happens when we need to choose clothes suitable for each other, shoes suitable for clothes, choose different wallpapers for the children's room, makeup, choose colors for our site and much more. The process of selecting several colors that combine with each other is called the construction of a color palette (gamut).

        In colouristics there are several methods for constructing a color palette (color gamma) based on the arrangement of colors relative to each other in the color circle and, usually, having the same brightness. Harmonious perception of which is not sufficiently substantiated from the physical point of view.

        The wave method of building color palette based on the relationship of color and acoustic waves, and also the concept of consonance (harmony) in music theory. Below is a more detailed description of the method.

        This site allows you to choose the most harmonious combination of colors for your site, clothing, interior, etc.

        The corresponding article was published on the site arxiv.orghttps://arxiv.org/abs/1709.04752. Results are available on our sitewavepalette.com.
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      • Lab tour: Functional Materials and Devices of Optoelectronics at ITMO University

          Today we’re taking a look at the Functional Materials and Devices of Optoelectronics Lab at ITMO University, the equipment it houses, and the projects underway at the facility. It is an international research facility located in the center of St. Petersburg. The staff is primarily occupied with the search for innovative materials (semiconductors, metals, and nanostructured oxides), and the manufacturing of next-gen micro- and optoelectronic gadgets. Here we take a look at the high-tech equipment it utilizes.

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        • Putting theory to practice: juggling work and study at the Department of Photonics and Optical Information Technology

            Master’s degrees are really useful. Postgrad education allows BA holders to put their new-found skills into practice, and secure great jobs further down the road. But students often need help assessing this choice, particularly if they majored in uncommon subjects — like photonics.

            To set the record straight, we talked to the people behind, and the graduates of our MA programs in photonics and optical computing. In this article you’ll learn about part-time work available for photonics students, graduates’ job-hunting prospects, and the academic career options that open up.

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          • AdBlock has stolen the banner, but banners are not teeth — they will be back

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          • Future economics for physicists

              Annotation. This article gives an analogy between the forces of nature and various types of money. A justification for the "money conservation laws" is made. Explanation of the IT-money phenomenon by analogy to physics laws is given, as well as gold and currency money. The transition from the gold and currency to the gold-currency-computing economy is considered. A reasonable assumption is made that the fourth type of money after gold, securities and IT money will be so-called "citation indices" or "ratings", which are similar in their properties to stock indices.


              What is money?


              This article is an attempt to understand what money is from the physics and econophysics points of view. Econophysics (economics and physics) is an interdisciplinary research field, applying theories and methods originally developed by physicists to solve problems in economics, usually those including uncertainty or stochastic processes, nonlinear dynamics and evolutionary games.

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            • Entropic force, transfer of information and a device for a radical fight against viruses on this basis

              Abstract.

              Even people far from physics know that the maximum possible data rate of any signal is equal to the speed of light in a vacuum. It is indicated by the letter «c», and it is almost 300 thousand kilometers per second. The speed of light in a vacuum is one of the fundamental physical constants. The impossibility of achieving speeds exceeding the speed of light in three-dimensional space is a conclusion from Einstein's Special Theory of Relativity (SRT).

              Usually, when claiming that STO prohibits the transmission of the information above the speed of light, an implicit assumption is made that there is no longer any other way than to “attach information” to a photon and transmit it. However, there is another way, which does not contradict, but «circumvents» the prohibition of SRT. The well-known physical hypothesis — the holographic principle (a tool of theoretical physics that is widely used today) indicates an interesting fact: “Phenomena that occur in three-dimensional space can be projected onto a remote “screen ” without losing information” — Leonard Susskind

              “Without information loss” means that a speculative projection operation is not required if we understand that our information Universe really exists only on a 2D surface of a holographic horizon (screen) with a single time coordinate, and the fundamental laws of physics are a natural way of encoding information with losses.
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            • The color of the Moon and the Sun from space in terms of RGB and color temperature

                It would seem that the question of the color of the Moon and the Sun from space for modern science is so simple that in our century there should be no problem at all with the answer. We are talking about colors when observing precisely from space, since the atmosphere causes a color change due to Rayleigh light scattering. «Surely somewhere in the encyclopedia about this in detail, in numbers it has long been written,» you will say. Well, now try searching the Internet for information about it. Happened? Most likely no. The maximum that you will find is a couple of words about the fact that the Moon has a brownish tint, and the Sun is reddish. But you will not find information about whether these tints are visible to the human eye or not, especially the meanings of colors in RGB or at least color temperatures. But you will find a bunch of photos and videos where the Moon from space is absolutely gray, mostly in photos of the American Apollo program, and where the Sun from space is depicted white and even blue.

                Especially my personal opinion is nothing but a consequence of the intervention of politics in science. After all, the colors of the Moon and the Sun from space directly relate to the flights of Americans to the Moon.

                I searched through many scientific articles and books in search of information about the color of the Moon and the Sun from space. Fortunately, it turned out that even though they do not have a direct answer to RGB, there is complete information about the spectral density of the solar radiation and the reflectivity of the Moon across the spectrum. This is quite enough to get accurate colors in RGB values. You just need to carefully calculate what, in fact, I did. In this article I will share the results of calculations with you and, of course, I will tell you in detail about the calculations themselves. And you will see the Moon and the Sun from space in real colors!
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              • Most common misconceptions in popular physics

                  Somewhere in an alternative Universe, based on MWI, I became a genius in physics. But in our Universe, I just read professional publications in physics, trying to keep myself up to date, meanwhile working as pizza delivery guy as DBA. Because of a slightly deeper knowledge of the subject it is almost impossible for me to watch the Discovery channel and other popular TV shows and the YouTube videos. I see nothing but oversimplifications, lies, and half-truths and can’t enjoy the shows.

                  I decided to compile a list of the most popular misconceptions. And the winner is...., or course, this one:

                  The Big Bang


                  Usually it is pictured like this:

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