Nondegenerate two-wave mixing for identifying and separating macromolecules

A method for determining a surface orientation of elements bound to nanoparticles in a medium, comprising:

• binding the elements to the nanoparticles to form bound element-nanoparticle aggregates;
• superposing first and second frequency-shifted optical waves having a variable frequency shift between them in the medium such that there is a gain in energy of the first optical wave with respect to the second optical wave;
• varying the frequency shift and measuring the gain while varying the frequency shift to determine the value of the frequency shift at which there is a peak in the gain;
• determining the radius of the bound element-nanoparticle aggregates based on the value of the frequency shift at which there is a peak in the gain;
• and
• determining the surface orientation of the elements based on the radius of the bound element-nanoparticle aggregates.

A method for measuring amounts of elements bound to nanoparticles in a solution, comprising:

• binding the elements to the nanoparticles to form bound element-nanoparticle aggregates;
• superposing first and second frequency-shifted optical waves having a variable frequency shift between them in the solution such that there is a gain in energy of the first optical wave with respect to the second optical wave;
• varying the frequency shift and measuring the gain while varying the frequency shift to determine the value of the frequency shift at which there is a peak in the gain;
• and
• assaying the solution to determine amounts of the bound element-nanoparticle aggregates in the solution based on the value of the frequency shift at which there is a peak in the gain.

A method for measuring a change in viscosity in a cell having a medium containing nanoparticles of known size, comprising:

• superposing first and second frequency-shifted optical waves having a variable frequency shift between them in the cell medium such that there is a gain in energy of the first optical wave with respect to the second optical wave;
• varying the frequency shift and measuring the gain while varying the frequency shift to determine the value of the frequency shift at which there is a peak in the gain;
• and
• determining a viscosity of the cell medium based on the value of the frequency shift at which there is a peak in the gain.

A method for determining a radius of elements suspended in a medium, comprising:

• binding the elements to nanoparticles to form bound element-nanoparticle aggregates;
• superposing first and second optical waves having the same frequency in the medium and moving the medium at a velocity to produce an effective Doppler shift between the first and second optical waves such that there is a gain in energy;
• varying the effective Doppler shift and measuring the gain while varying the effective Doppler shift to determine the value of the effective Doppler shift at which there is a peak in the gain;
• determining the radius of the bound element-nanoparticle aggregates based on the value of the effective Doppler shift at which there is a peak in the gain;
• and
• determining the radius of the elements based on the radius of the bound element-nanoparticle aggregates.