Manas Ranjan Sahu

Postdoctoral Associate @UofR
Former Postdoc at Quantronics @CEAParisSaclay
MS+PhD @iiscbangalore, Undergrad @ravenshaw150

[Manas Ranjan Sahu @Manas_Physics]

Just like a flashing strobe light makes a periodic motion appear frozen, we created a 'quantum strobe light' using the spin of confined electrons. This lets us freeze the chaotic behavior of thousands of Si-29 nuclear spins at will. Happy reading!
https://t.co/y79wHJxbAl

[outside five sigma @jwt0625]

check out this thread if you are curious and want more about how this DQD got killed

[Manas Ranjan Sahu @Manas_Physics]

All these experiments are part of a somewhat failed experiment, but full of new knowledge, as each time we cool down a new sample we always learned something new. In a broader sense experiments never fail, they only tell the nature’s reality!

[Manas Ranjan Sahu @Manas_Physics]

Found this inetersting thread that highlights our work which we recently posted in arxiv (https://t.co/vA8R399edf). I will share the story behind this work in the thread below!

Happy reading!

[outside five sigma @jwt0625]

before my lithium niobate (LN) appreciation thread, i gotta trash talk about it one more time: pyroelectric effect.

as the name suggests, you get electric field from temperature change (but not vice versa as would be the case for a lot of other effects since here entropy is involved. The other direction is electrocaloric effect). This means you can do cool stuff with it, such as rapid heating of a chip to get 100 kV (https://t.co/8BXjxZgVi8), but it also means a lot of horrible unexpected stuff could happen if you don't know about it.

when you bake your chip during fab on a hotplate, the electric field from the temperature change could fry the devices, or even fry and crack the whole substrate. People would add conductive coating or even wrap the chip in aluminum foil during processing to provide discharge paths. And of course it's dependent on crystal cut, and usually worse on z-cut. You'll find literature from the 1980s complaining about channel waveguide MZI drifting more on z-cut LN (https://t.co/4xCV9CdFFZ).

here is another example where electric field from a LN chip ESD-ed a device on *another* chip during cooldown to 4 K (https://t.co/gtcZvc3RSu). They have to add shielding electrodes to protect those devices and they would survive, and the IDTs on LN chip would still get fried.

pyroelectric effect also bothered me a few times, and I was not even on z-cut. I had some x-cut thin film LN devices on silicon substrate, mostly released (i.e. floating) with a few anchor points, that suddenly started mysteriously collapsing when cooling down to 4 K. I ruled out CTE mismatch because that won't explain why it suddenly started happening, but it could be pyroelectric + electrostatic pull-in because I may have moved to a new wafer with better crystal quality and worse discharge. So I put extra aluminum electrodes everywhere to short different LN components to the silicon substrate, and they stopped the collapse..

[Manas Ranjan Sahu @Manas_Physics]

Floated QD gates, nothing burns. Defining a ground potential between LN and Si/SiGe protects QDs but the SAW still blows!

[Manas Ranjan Sahu @Manas_Physics]

@jwt0625 Thanks Wentao! It is an extendend MC plate, it looks a bit messy because of the many RF components needed to measure our devices. Contents of the banner are highlights from my previous lab, Quantronics group at CEA Paris-Saclay!

[Arindam Ghosh @ArindamPhysics]

Building deeptech Section 8 companies, that will become self sufficient in next 5/6 years, is going to be an exciting challenge. IT majors in India are heavily biased towards soft technologies... developing hardware will require persistence and patience.
https://t.co/haNZHVNOW8

[Manas Ranjan Sahu @Manas_Physics]

@MartaPitaVidal @PhysRevB Thanks Marta!

[Manas Ranjan Sahu @Manas_Physics]

Our recent work is out in @PhysRevB. During this work i learned a bit of a new field (circuit QED), and more than that a bit of how to do science from the wonderful Quantronics team.

Hopefully this adds some new knowledge to the community. Happy reading!
https://t.co/gUveIf9YRS

[Shashi Tharoor @ShashiTharoor]

Hope @TheKeralaPolice are aware of this video. These disgusting & inhumane practices are also illegal. Action should be taken:

https://t.co/TNLmxtYQJy