Freqency-Transient Study and Segerated Step Problem

Dear all,

I’m modeling a laser-alloy particle interaction using Comsol 5.2. A alloy particle of 50um in diameter is placed on a silicon substrate. A laser beam of 5kW/cm^2 is incident from the top. The wavelength is 532nm. The alloy particle will absorb some of the laser energy, and the rest of the laser beam will scatter away. My aim is to calculate the temperature rise and distribution in the alloy particle, as it will absorb the incident laser beam. The substrate is used for the mechanical stability and the facility of the mesh, as introduced in the Microwave Oven Application. A PML is used to absorb the scattered laser beam. The incident beam is defined by port.

Since the geometry is much larger than the wavelength, I used Electromagnetic Waves, Beam Envelopes interface coupled with Heat Transfer in Solids interface.

As I used the Frequency-Transient study step and the Default Solver and computed it, an error showed up:
Failed to find consistent initial values.
Segregated Step 2
Second argument must be real.
Last time step is not converged.

I thought the second argument of the segregated step 2 is the S-parameter? I checked several times and didn’t know where the problem is. Please give me some hint!

Thanks in advance,
Chen.