Category Archives: Blog

Six Great Works of Fiction

April 4, 2021

Growing up in the 80s-90s in Western Anatolia was nice. The sunny summers felt endless and I had my share of playing in the street with my friends all day long. I was luckier than most other kids around me though: I grew up in two houses (my parents and my grandparents) that were full of books. Thanks to my uncle’s colorful Asterix and Storm series, I was hooked into books even before I learnt reading. So I can officially say that I owe my current self to many great and not-so-great books. Fictions, especially, improved my ability to see events from someone else’s perspective. And some exceptional books, like these six, showed me that human intelligence and creativity was far more advanced than I had assumed.

The Glass Bead Game / Hermann Hesse

Hermann Hesse imagined a world that the intellectual elites are free to follow their curiosity and work with no other practical responsibility. The main character is questioning if an intellectual can be content with such a life or there is more to life than that. The Glass Bead Game introduced me to Hermann Hesse, probably the most intelligent author I have come across. I love the original title in German: Das Glasperlenspiel.

The Gods Themselves / Isaac Asimov

How would a civilization from another universe interact with us? What would it be like if a species needed 3 sexes to procreate? How can a single human being named Isaac think of all these and write an amazing novel?

The Silmarillion / J. R. R. Tolkien

The Silmarillion backs The Lord of the Rings with a complex and fantastic mythology. Tolkien invented species, languages and religions from scratch. This book got into my dreams more than any other.

Watchmen / Alan Moore

Watchmen is a literary masterpiece. It multiplied my respect and interest for graphic novels. The author and the artists invested significant time and energy in the development of the characters, story and graphics. A striking example: a minor character in Watchmen is reading a fictional comic book, which we also follow through a zoomed-in view. This comic book (Tales of the Black Freighter) would be a standalone masterpiece.

The Atlas of Misty Continents / İhsan Oktay Anar

Is there really a difference between dreaming and being awake? In this novel, an Ottoman scholar from Early Modern Period is trying to draw an exact map of the world. His method is interesting though: he takes a drug, sleeps and travels only in his dreams. His son then takes over the adventure which takes him from Istanbul to a secret mission in Central Europe, while the reader is lost in magical realism. It seems there is no English translation of this book as of 2021, although it is available in French, German and Korean.

Steppenwolf / Hermann Hesse

This is a tricky one to summarize. It leaves the taste of a hallucinogenic drug, whenever I read it. It is hard to believe it was written in the 1920s, given the open-mindedness of the author and the characters.

Çağrı Üzüm

3D Printing in Sub-Micron Scale – Part 2

Part 1: Focused Electron Beam Induced 3D Nanoprinting

Part 2: 2-Photon Polymerization

Part 3: AFM Based 3D Printing


January 14, 2018

Part 2: 2-Photon Polymerization

This is the second part of the series 3D Printing in Sub-Micron Scale. The first part was about a truly nanoscale 3D printing technology realized in a scanning electron microscope. Here we focus on the most commercially successful sub-micron 3D printing technology: Photopolymerization via two-photon absorption aka two photon polymerization (2PP). Before going into any technical details please watch this stunning short video made by TU Wien:

Isn’t this something? Of course 2PP is not only a high-tech toy to build micro-castles or cars. The following list includes just some of the current applications according to Nanoscribe, a manufacturer of 2PP 3D printers:

Some applications of 2PP sub-micron 3D printing. Taken form nanoscribe.de

The printing principle is similar to the commonly used stereolithography. A vat of liquid photopolymer resin is cured locally with a laser. Shorty, wherever the laser is focused, the ingredients in the vat will polymerize / cross-link and will turn into an insoluble solid. Prof. Bill Hammack (engineerguy) made arguably one of the best videos on 3D printing, especially on DLP stereolithography:

How does 2PP deliver a high-resolution 3D printing?

In a macroscale stereolithography 3D printer as the one in the video above, a UV laser is used as the light source. The process is a single photon absorption: photopolymer is cured (solidified) if a single photon is absorbed by each initiator. The probability of the initiator molecule to absorb one photon is pretty high, meaning that polymerization would occur not only at the exact point at which the UV laser is focused but also around that point, where the laser intensity is lower. This undesired polymerization out of focus decreases the printing resolution.

Sub-micron 2PP 3D printing, in contrast, uses a laser in the visible range. Individual photons in visible laser have less energy than those in the UV laser. In order for an initiator to be activated, it has to absorb two photons, nearly simultaneously. For quantum reasons the probability of two-photon absorption is so low that it only takes place where the laser is focused (due to the tremendous amount of photons in a very small volume). Obviously if no polymerization takes place out of focus, printing resolution increases. The image below was taken from Microlight, a French manufacturer of 2PP 3D printers. It shows the activated areas in case of single-photon and two-photon absorption.

Single-photon vs two-photon excitation (Image taken from microlight.fr)

I really hope this short post makes 2PP sub-micron 3D printing a bit clearer. As a nanoscientist, I am sure its real rise is still to come.

Çağrı Üzüm


Disclaimer: This is a personal blog. I write about things that I find exciting and think are worth sharing. The content was not influenced by advertising or sponsorship. There may be other great products from other companies that I am not aware of (actually I would appreciate if you could write to me if you know any).

Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

3D Printing in Sub-Micron Scale – Part 1

Part 1: Focused Electron Beam Induced 3D Nanoprinting

Part 2: 2-Photon Polymerization

Part 3: AFM Based 3D Printing


August 9, 2017

3D printing or its industry-common synonym additive manufacturing is already an indispensable part of many industries. Traditionally used for prototyping, 3D printing currently enables manufacturing of highly complex structures e.g. prosthetics, machine parts, etc., thanks to its layer-by-layer manufacturing mentality. There are many widely used 3D printing technologies out there, that have mostly nothing to do with each other. If you are interested in these technologies, please visit one of the best technical resources I came across online: the 3D Hubs website. If you are also interested in knowing how you can 3D print a model of a city or an army of nanorobots on the surface of a single hair, just keep on reading these post series. Continue reading

Intuition in Research

July 17, 2017

Trusting and following intuitions often lead to a significant progress in scientific research. I have been trying to better understand the nature of intuition and make use of this fascinating tool. What we should all understand is that intuition really exists and it is not something abstract or mysterious. Although there are different views on how it functions, most modern scientists agree that it is a part of our extremely complex biological machine. In this post I will write about the role of intuition in an average research project and how a researcher should seek ways to exploit it, solely based on my own research experience. Continue reading

Three Exciting Advances in Atomic Force Microscopy

July 8, 2017

I previously wrote shortly about atomic force microscopy (AFM). With this amazing tool, surfaces can be mapped with a resolution of several nanometers, that is several tens of atoms. Imaging the surface topography is maybe the most common use of an AFM but the technique offers many other possibilities ranging from nanomechanical measurements to nanoprinting. I have been in contact with AFM since 2008 and many manufacturers have introduced stunning new applications since then. What I want to write about today is 3 very recent advances in the AFM technology that are already commercially available or will be soon. Please note, the list is far from being a result of a complete review. Continue reading

Playing in a Nanoscale Playground: Atomic Force Microscopy (AFM)

July 7, 2017

Among all the research I have done up to now, I had the most fun while pushing the limits of atomic force microscopy (AFM aka SFM – scanning force microscopy). I have been ever since fascinated by being able to generate images of smallest surfaces imaginable, sense forces between the smallest dust particles, the ability to manipulate things with the precision of several tens of molecules and reflecting the power of software to the physical world in nearly atomic scale. I wanted to pay my tribute to this magic tool by writing shortly about it. Continue reading