The code examples make use of **OTS — the Optical Trapping Software**.

You can leave comments or signal bugs in the comment form below.

### Chapter 2 — Ray Optics

### Scattering of a ray on a spherical particle

1 file(s) 1.24 KB

### Counter-propagating trap in geometrical optics

1 file(s) 1.42 KB

### Optical tweezers in geometrical optics

1 file(s) 1.41 KB

### Chapter 4 — Optical Beams and Focusing

### Field propagation along the z-axis

1 file(s) 1.09 KB

### Simulation of a Bessel beam

1 file(s) 0.95 KB

### Focal field calculation

1 file(s) 0.91 KB

### Focal field calculation with interface

1 file(s) 1.00 KB

### Dipole forces near a focal field

1 file(s) 1.33 KB

### Chapter 5 — Electromagnetic Theory

### Visualization of spherical harmonics

1 file(s) 0.98 KB

### Visualization of vector spherical harmonics

1 file(s) 0.88 KB

### Visualization of multipoles

1 file(s) 0.93 KB

### Multipole expansion of a plane wave

1 file(s) 1.39 KB

### Mie scattering

1 file(s) 1.24 KB

### Optical force exerted by a plane wave on a spherical particle

1 file(s) 1.79 KB

### Optical force exerted by a focused beam on a spherical particle

1 file(s) 2.17 KB

### Chapter 6 — Computational Methods

### Checks Clebsch-Gordan coefficients

1 file(s) 1.71 KB

### Force by a plane wave on a sphere

1 file(s) 1.45 KB

### Torque by a plane wave on a sphere

1 file(s) 1.74 KB

### Force on a sphere by a focused beam

1 file(s) 2.75 KB

### Translation of T-matrix

1 file(s) 1.66 KB

### Rotation of T-matrix

1 file(s) 1.97 KB

### Comparison of forces and fields with a focused beam

1 file(s) 2.48 KB

### T-matrix sphere

1 file(s) 1.39 KB

### T-matrix cluster

1 file(s) 2.47 KB

### T-matrix inclusions

1 file(s) 2.43 KB

### Chapter 7 — Brownian Motion

### Molecular dynamics simulation of a Brownian particle in a fluid

1 file(s) 1.65 KB

### Lennard-Jones potential

1 file(s) 0.71 KB

### Random walk simulation

1 file(s) 0.92 KB

### Biased random walk simulation

1 file(s) 0.95 KB

### Free diffusion of a Brownian particle in 2D

1 file(s) 0.84 KB

### Brownian motion simulation

1 file(s) 0.91 KB

### Brownian motion in a diffusion gradient

1 file(s) 0.91 KB

### Position variance of an optically trapped particle

1 file(s) 0.82 KB

### Simulation of Brownian motion in optical tweezers

1 file(s) 0.78 KB

### Chapter 9 — Data Acquisition and Optical Tweezers Calibration*

### Simulate the image of a particle acquired by a digital camera

1 file(s) 1.29 KB

### Digital video microscopy

1 file(s) 0.90 KB

### Si_Ternary.tif.zip

1 file(s) 1,162.19 MB

### Forward scattering position detection

1 file(s) 3.38 KB

### Backward scattering position detection

1 file(s) 3.02 KB

### Calibration using potential method

1 file(s) 0.83 KB

### Calibration using equipartition method

1 file(s) 0.92 KB

### Calibration using mean square displacement method

1 file(s) 0.87 KB

### Calibration using autocorrelation function method

1 file(s) 0.88 KB

### PCA transform to decorrelate correlated signals

1 file(s) 0.91 KB

### Calibration using power spectral density method

1 file(s) 0.90 KB

### trajectory.mat

1 file(s) 43.27 MB

### trajectoryxy.mat

1 file(s) 43.27 MB

### Chapter 10 — Photonic Force Microscope

### Brownian motion in a rotational force field

1 file(s) 0.81 KB

### Chapter 11 — Wavefront Engineering and Holographic Optical Tweezers*

### Generation of holographic optical traps

1 file(s) 1.01 KB

### Generation of Laguerre-Gaussian beams

1 file(s) 0.90 KB

Hi. I am trying to download trajectory.mat and trajectoryxy.mat but its giving a network error. Other files are downloading easily.

Hi. This sometimes happens because they are large files. I’ve sent you by email some dropbox links to download them.

Hi, I cannot download the Si_trajectory.tif.zip either. I think it is due to file size. Is there a solution?!

Regards,

Asa

This sometimes happens because of the size of the file.

I’ll send you the file by WeTransfer.

Could you please give an example of how to model an arbitrary shaped particle for optical tweezing with a focused beam? I only could find examples with predefined 3D shapes that toolbox has, but I am wondering how I should model a different shape.

If you want to do this within the geometrical optics package, you need to implement a new object extending “Particle” and implementing the abstract methods. In fact, the objects “ParticleSpherical”, “ParticleCylindrical” and “ParticleEllipsoidal” are examples of this process.

It looks there is no function “BrownianMotion1DOT”.

How can I work the code in Chapter 7 “Brownian motion”?

Thank you

Hi,

the function is in the folder bm of the OTS software.

Hello Prof. Volpe,

I am very delighted to read the book and solve the constituting tutorial. I would like to ask a question regarding the phase mask that we project on a spatial light modulator.

I am working with holographic tweezer and wrote a code using GS Algorithm as described in Chapter-11. I found that at every instant of time I run code, the phase mask is different as the initial random phase are different. Interestingly, the desired pattern is obtained.

Is this obvious or It can be solved.

Your suggestion would be helpful

Hi,

Thank you for your feedback and question.

Yes, you are right that the GS algorithm is stochastic and will produce different phase mask each time it’s run. In fact, multiple phase mass produce the same intensity (e.g., think of a grating and its translations). Therefore, this is not a problem, just a feature of phase masks.

Hello Prof. Volpe,

Thank you very much for the clarification.

Thank you!

Hello Prof. Volpe,

Thank you so much for providing such a comprehensive set of matlab implemented codes for such applied examples and your kind attitude to make them free to access.

I cannot download these files:

“Si_Ternary.tif.zip”

“trajectory.mat”

“trajectoryxy.mat”

It would be so appreciated if you help me.

Thanks again.

Best regards.

focustm.m – Force on a sphere by a focused beam,

in this section it shows like this

Unrecognized function or variable ‘BeamGauss’.

Error in focustm (line 34)

b = BeamGauss(Ex0,Ey0,w0,R,Nphi,Nr);

how to resolve these things sir.

Probably you have not loaded the ots package