Building an Ultrasound Generator

Question

I need to generate ultrasound with a frequency of 1.5 MHz. The ultrasound should be pulsed as shown here

An ultrasound pulse should be 200 µs long, a pause (no ultrasound) is 800 µs long. The desired intensity should be 30 mW/cm^2 and upwards.

The problem is, I have no idea where I would even start. I have basic to advanced theoretical knowledge of electronics and physics, I have soldered once, but that's about it.

So I need you for guidance :).

What device do I need to generate the ultrasound? I guess a normal speaker won't do.

What do I have to do to generate such a pulse form and the desired frequency?

What other items do I need?

I prefer pre-built components (like an ultrasound generator which can give me the above pulse form and frequency) over having to build everything myself; but if I have to build something myself, I'll take on the challenge and hopefully learn something from it.

Any thoughts or pointers are greatly appreciated.

(If my question is too broad, I'll be happy to provide more details.)

Thank you.

Answer 1

Ultrasonic transducers are used for several applications on boats.

Alas, I haven't seen any tuned for exactly 1.5 MHz, but perhaps a transducer tuned to some slightly different higher or lower frequency will be adequate for your application:

Parsonics "14 kHz to 4.5 MHz"

Airmar "4.5 MHz"; Airmar "30 kHz to 300 kHz"

NKE Marine "4.5 MHz"

Answer 2

I think your best option for this frequency is to look a medical ultrasound transducer. Places like BK Precision make them but they will be expensive. Here is an 1.5MHz option from a unknown supplier on Alibaba that may be suitable for your application, though you may want to ask about a datasheet, or at the very least instructions for driving it properly.
As far as pulsing goes, a transistor switch with a microcontroller (or even e.g. 555 timer) to could be easily set up to control things.