Experimental Modern and Quantum Physics for Do-It-Yourself Science Enthusiasts 

Facebook Flickr LinkedIn YouTube RSS
magnify
formats

Welcome to diyPhysics.com !

Welcome to diyPhysics.com, a blog dedicated to the advanced do-it-yourselfer interested in modern and quantum physics!

David and Shanni PrutchiWe are the authors of the book Exploring Quantum Physics through Hands-On Projects,” which will help you understand Quantum Physics through hands-on experiments that you can conduct at school or at home!

Our book will guide you in the construction and use of setups to reproduce the key experiments that have brought us to our current understanding of the quantum world. Importantly, all of the experimental equipment can be built out of relatively inexpensive materials that are readily available at the hardware store or from on-line vendors of electronic surplus.

The projects range from simple measurements of Planck’s constant all the way to testing violations of Bell’s inequalities using entangled photons. The project descriptions are targeted to an audience with basic experience in electronic prototype construction. The circuits actually work, and the schematics are completely readable.

We hope that you enjoy reading our blog!

David and Shanni Prutchi

www.prutchi.com

 
 Share on Facebook Share on Twitter Share on Reddit Share on LinkedIn
Comments Off on Welcome to diyPhysics.com !  comments 
formats

Modern/Quantum Physics Instructors: Adopt the Textbook

Teachers, instructors, and professors at accredited higher-learning institutions may request an evaluation copy of the book from J. Wiley & Sons.

 Shanni building and testing photoelectric effect setup

Why should you adopt this book as your Quantum Physics lab course textbook?

Our book explains Quantum Physics through hands-on experiments that the reader can perform at school. Throughout the book we guide the reader in the construction and use of setups to reproduce the key experiments that have brought us to our current understanding of the quantum world. Importantly, all of the experimental equipment can be built by the reader out of relatively inexpensive materials that are readily available at the hardware store or from on-line vendors of electronic surplus. Read more…

 
 Share on Facebook Share on Twitter Share on Reddit Share on LinkedIn
Comments Off on Modern/Quantum Physics Instructors: Adopt the Textbook  comments 
formats

DOLPi Visor Replication by Andrew Gliesman

DOLPi Visor replication by Andrew GliesmanAndrew Gliesman sent me these pictures of his DOLPi Visor replication along with a very kind note.

…I wanted to thank you for your excellent paper on the DOLPi Polarimetric Camera.  The amount of technical detail combined with providing a solution of a real world humanitarian problem made it special to me.

I recently built a DOLPi Visor and wanted to share my alternative form-factor with you (see photos.)  With respect to the build notes, everything was spot on – I just found that I needed to clean the adhesive residue after removing a polarizer film on the LCP (perhaps this had to do with the brand – I couldn’t find the MASK brand on Amazon.)…

The point about the adhesive is interesting.  Indeed, the adhesive remains transparent after removing the polarizer film, but becomes cloudy if scratched.  I found that the best way to remove it is to loosen it with a drop of “Goof-Off” and then scraping it with a sharp razor blade.

Thanks Andrew!

DOLPi Visor replication by Andrew Gliesman

 

 
 Share on Facebook Share on Twitter Share on Reddit Share on LinkedIn
No Comments  comments 
formats

Nuclear Magnetic Resonance in Cobalt with a Grid Dip Meter

heathkit-gd-1b-grid-dip-meter

Hackaday published an excellent article by Al Williams titled “The Grid Dip Meter: Forgotten Instrument”.   This reminded me of an interesting physics experiment that really helped me back in college to understand the mechanism behind nuclear resonance.  The experiment was described as a note in the American Journal of Physics in 1963:  R.J. Blume, Demonstration of Nuclear Magnetic Resonance in Cobalt with a “Grid Dip” Meter, Am. J. Phys. 31, 58 (1963).  Here is the text of that note (no figures accompanied it):

Demonstration of Nuclear Magnetic Resonance in Cobalt with a “Grid Dip” Meter

R.J. BLUME

IBM Watson Laboratory, Columbia University,

New York 27, New York

THE nuclear magnetic resonance (NMR) absorption in ferromagnetic materials is tremendously enhanced compared with that in all other substances. By far the most intense NMR absorption yet reported is that of the Co59 nucleus in bulk cobalt.1• 2 At room temperature, the internal magnetic field at the cobalt nucleus is about 210 kG. The nuclei precess in this field at 213.1 Mc, and will absorb energy at this frequency from an rf oscillator coupled to the cobalt sample. No external magnetic field need be applied to the cobalt; a strong external field will in fact destroy the resonance.

All that is required to observe the resonance is some powdered cobalt, and a low-powered rf oscillator equipped with a meter which indicates grid current, i.e. a “grid clip” meter.3 Ordinarily, the tuned LC circuit of the oscillator is unloaded, and the grid current is relatively high. When energy is absorbed from the tuned circuit of the oscillator by a nearby resonant circuit, the grid current shows a dip. With a model 59 Megacycle Meter,4 the curved end of the tuning hairpin need only be held flat against the bottom of the bottle of cobalt. As the oscillator is tuned carefully through 213.1 Mc, a small clip of grid current will be observed. The absorbing “resonant circuit” in this case is the system of Co59 nuclei.

The 213.1-Mc resonance arises from nuclei of atoms located in the abundant face-centered cubic crystal structure. Nuclei of atoms in the less abundant hexagonal closepacked structure see a slightly larger magnetic field, and therefore resonate at about 221 Mc. 5 If a little cobalt is placed just inside the curved end of the hairpin, the 213.1-Mc absorption dip will become stronger, and it should then be possible to discern the 221-Mc absorption as well. Some weaker resonances are also present, but additional equipment is usually needed to see them. The 213.1-Mc resonance can be seen with the Heathkit model GD-1B grid dip meter.

A grid dip meter is normally coupled weakly to the circuit under test, in order to avoid mutual detuning, and the frequency dial is calibrated accordingly. The proximity of the bulk cobalt to the hairpin has two gross effects on the grid dip meter, in addition to providing resonant absorption of nuclear origin. Firstly, the added stray capacitance reduces the oscillation frequency by roughly 5 to 10% below that indicated on the dial. Thus, to obtain oscillation at 213.1 Mc when the cobalt is in place, the dial has to be set at some higher reading. The actual frequency has to be measured by standard techniques. 6 Secondly, resistive loading of the oscillator reduces the amplitude of the rf oscillation, and may stop it entirely if too much cobalt is brought too close. The best NMR sensitivity is obtained when oscillation is barely sustained.

Only the cobalt resonance is detectable by the means described here. The sample used in the present work was 300 mesh, assay 98% minimum, Ni 0.6%, obtained from the Fisher Scientific Company (catalog number C363).

1 A. C. Gossard and A. M. Portis, Phys. Rev. Letters 3, 164 (1959).

2 A. M. Portis and A. C. Gossard, J. Appl. Phys. 31, ZOSS (1960).

3 See any recent edition of the annual Radio Amateur’s Handbook (American Radio Relay League, West Hartford, Connecticut).

4 A grid dip meter manufactured by the Measurements Corporation, Boonton. New Jersey.

5 R. Street, D.S. Rodbell, and W. L. Roth, Phys. Rev.121, 84 (1961).

‘F. E. Terman and J.M. Pettit, Electrnnic Measurements (McGrawHill Book Company, Inc., New York, 1952), Chap. S.

 
 Share on Facebook Share on Twitter Share on Reddit Share on LinkedIn
Comments Off on Nuclear Magnetic Resonance in Cobalt with a Grid Dip Meter  comments 
formats

Video of Shanni’s Lecture on Entangled Photon Generation at HaD SuperCon

Shanni_HaD_IMG_2111_600px

Shanni presented on “Construction of an Entangled Photon Source for Experimenting with Quantum Technologies” at the 2015 Hackaday SuperConference.

Her lecture has been uploaded by Hackaday and is available now available online.  CLICK HERE for the link to the HaD Blog and Video.

Shanni Prutchi presents at HaD SuperCon on Entangled Photon Generation

 

 
 Share on Facebook Share on Twitter Share on Reddit Share on LinkedIn
Comments Off on Video of Shanni’s Lecture on Entangled Photon Generation at HaD SuperCon  comments 
formats

DOLPi DIY Polarimetric Camera Awarded 5th Place in 2015 Hackaday Prize

David Prutcho PhD 5th place Hackaday prize winner

The DOLPi Raspberry Pi-based polarimetric cameras received 5th place in the 2015 Hackaday Prize.  Winners for this year’s prizes were announced on stage at the Hackaday Superconference on November 14, 2015.

The DOLPi project involved the development and construction of two low-cost polarimetric camera types based on the Raspberry Pi 2. DOLPi-MECH (and its productized IR-VIS-UV version DOLPi-UI) is a filter-wheel-type camera capable of performing full Stokes analysis, while the electro-optic based DOLPi-EO camera performs full linear polarimetric analysis at higher frame rate. Complete Python code for polarimetric imaging is presented. Various applications for the cameras are described, especially their use for locating mines and unexploded ordinance in humanitarian demining operations.

CLICK HERE for a complete project description including detailed construction instructions and Python code in pdf format.

 

 

 
 Share on Facebook Share on Twitter Share on Reddit Share on LinkedIn
Comments Off on DOLPi DIY Polarimetric Camera Awarded 5th Place in 2015 Hackaday Prize  comments 
formats

DOLPi Final Version of Whitepaper and Video

 

The final version of the DOLPi whitepaper is now available here: DOLPi_Polarimetric_Camera_D_Prutchi_2015_v5

 
 Share on Facebook Share on Twitter Share on Reddit Share on LinkedIn
Comments Off on DOLPi Final Version of Whitepaper and Video  comments 
formats

DOLPi is a Hack-a-Day Prize Finalist!

HackadayPrize

Hack-a-Day just announced the finalists for the 2015 Prize, and DOLPi is one of them!  Hack-a-Day Prize 2015 Finalists for the announcement.

Here is the list of Finalists:

 

 

 
 Share on Facebook Share on Twitter Share on Reddit Share on LinkedIn
Comments Off on DOLPi is a Hack-a-Day Prize Finalist!  comments 
formats

New Liquid Crystal Panel AC driver for DOLPi

AC Driver for the DOLPi Polarization Camera by David Prutchi PhD

Although the circuit of shown so far as the liquid crystal panel’s AC driver works well, I’m not too happy with the intrinsic non-linearity of the FET.  Because of this, today I designed and tested an alternative, a bit more complex, but I believe more elegant design.  In the circuit shown above, the LCP drive amplitude tracks linearly with the DAC’s output.

The non-inverting amplifier built around U1 approximately doubles the output of the DAC. This voltage is then presented to an H-bridge implemented by the analog switches in U2. The H-bridge produces a continuous biphasic train at a frequency given by the oscillator built around U3A and U3B. U4 doubles the +5V coming from the Raspberry Pi to power U1 and U2. The LCP is connected between the legs of the H-bridge.

 
 Share on Facebook Share on Twitter Share on Reddit Share on LinkedIn
Comments Off on New Liquid Crystal Panel AC driver for DOLPi  comments 
formats

New Version of DOLPi Whitepaper Released (v4)

DOLPi polarimetric cameras by David Prutchi

A new version of the DOLPi polarimetric camera whitepaper has been released at: DOLPi_Polarimetric_Camera_D_Prutchi_2015_v4

 
 Share on Facebook Share on Twitter Share on Reddit Share on LinkedIn
Comments Off on New Version of DOLPi Whitepaper Released (v4)  comments 
formats

DOLPi Whitepaper V.3 Published

DOLPi polarimetric cameras by David Prutchi

The new version of the whitepaper is available at: DOLPi_Polarimetric_Camera_D_Prutchi_2015_v3

 
 Share on Facebook Share on Twitter Share on Reddit Share on LinkedIn
Comments Off on DOLPi Whitepaper V.3 Published  comments 
formats

New DOLPi Project Overview Video Uploaded

 

 
 Share on Facebook Share on Twitter Share on Reddit Share on LinkedIn
Comments Off on New DOLPi Project Overview Video Uploaded  comments 
formats

New, Complete Version of DOLPi Whitepaper Available

DOLPi polarimetric cameras by David Prutchi

A new, complete version of the whitepaper on DOLPi is available for download here:  DOLPi_Polarimetric_Camera_D_Prutchi_2015_v2

This paper presents the development and construction of two low-cost polarimetric cameras based on the Raspberry Pi 2.  “DOLPi-MECH” is a filter-wheel-type camera capable of performing full Stokes analysis, while the electro-optic based “DOLPi” camera performs full linear polarimetric analysis at higher frame rate.  Complete Python code for polarimetric imaging is presented.  Various applications for the cameras are described, especially its use for locating mines and unexploded ordinance in humanitarian demining operations.

 
 Share on Facebook Share on Twitter Share on Reddit Share on LinkedIn
Comments Off on New, Complete Version of DOLPi Whitepaper Available  comments 
formats

DOLPi_Mech: A Slower But Accurate Imaging Polarimeter

DOLPi-Mech Filter Wheel Polarimetric Camera David Prutchi Ph.D.

The image that the liquid-crystal-panel-based DOLPi takes at “45 degrees” is not strictly that, which is why I state in the paper:

“Bossa Nova’s method is straightforward if laboratory optical-grade components are used. These are very expensive and out of reach for most private enthusiasts. However, I found through experimentation that a welding mask LCP and a polarizer sheet can also give very satisfactory results.”

In reality, the LCP driven half-way acts as a quarter-wave plate, and hence the strict interpretation of the analysis at this level is for circular polarization rather than linear polarization at 45 degrees.

I didn’t want to go into a thorough explanation of polarization optics to keep the project accessible, but based on my experiments, I’m convinced that DOLPi’s “45 degree image” indeed contains a dominant 45 degree component when observing linearly polarized light.

This weekend I decided to build a mechanical filter-wheel-based polarimetric camera to serve as a basis for comparison to the LCP_based DOLPi. This camera is much slower than the LCP-based DOLPi because of the mechanical switching of filters, but it provides the data necessary for complete Stokes imaging (including the fourth Stokes parameter describing circular polarization). The pictures that it produces are of excellent quality!

Read more…

 
 Share on Facebook Share on Twitter Share on Reddit Share on LinkedIn
Comments Off on DOLPi_Mech: A Slower But Accurate Imaging Polarimeter  comments 
formats

DOLPi is a Hack-a-Day 2015 Semifinalist!

HackadayPrize

“From: no-reply-projects@hackaday.com

Sent: Monday, August 24, 2015 9:39 AM

To: david@

Subject: Your Project is a Semifinalist in the 2015 Hackaday Prize!

Dear David Prutchi,

Congratulations! We think your DOLPi – RasPi Polarization Camera is awesome and you are one of our top 100 picks for the Hackaday Prize. You are advancing to the next round.

What happens now? We are announcing this in a short bit on Hackaday and this is a good time for you to tell everyone that your product is now in the running for a trip to space! Spaaaace!

…”

 
 Share on Facebook Share on Twitter Share on Reddit Share on LinkedIn
Comments Off on DOLPi is a Hack-a-Day 2015 Semifinalist!  comments 
formats

Hack-A-Day 2015 Prize DOLPi Submission Video

Hi! DOLPi is a low-cost polarization camera based on the Raspberry Pi.

Like intensity and color, polarization is another property of a light wave.

Humans cannot sense polarization, but many animals like cuttlefish and insects have polarization-sensitive vision that they use for navigation, finding water, and detecting transparent prey.

This is DOLPi – it is completely self-contained and easy to build. In spite of its simplicity, it holds truly awesome power for the development of brand new scientific and commercial applications!

Read more…

 
 Share on Facebook Share on Twitter Share on Reddit Share on LinkedIn
Comments Off on Hack-A-Day 2015 Prize DOLPi Submission Video  comments 
formats

DOLPi’s first pictures outside the lab

Image taken with DOLPi Polarization camera (c)2015 David Prutchi, PhD

These are polarization images taken with DOLPi.  Colors represent Angle of Polarization

Image taken with DOLPi Polarization camera (c)2015 David Prutchi, PhD

 

 
 Share on Facebook Share on Twitter Share on Reddit Share on LinkedIn
Comments Off on DOLPi’s first pictures outside the lab  comments