Yes and no. The Triolet does not have any integrated dimmer, only the inline on/off switch. While it can be plugged into a dimmer with Edison or Schuko in/outs (based on if you hav the US or EU version), dimming is based purely on the bulb that is used.
If you’re using the Triolet with a Tungsten Mogul bulb, Edison, or GY9.5 via adapters, these bulbs can be successfully used on a dimmer or variac of the appropriate wattage and voltage (again dependent on the bulb used). We’d recommend a 1,000W dimmer, as this is the maximum wattage of the Triolet, and lower wattage bulbs can be used safely as well. However a 300W or 600W dimmer with a 1,000W bulb is a major electrical hazard. Keep in mind that dimming a tungsten bulb also decreases the color temperature, resulting in a warmer light.
When using the Triolet with Fluorescent bulbs, unless the bulb is specified to be suitable for operation on a dimmer, the bulb may begin to flicker or buzz as a result of receiving insufficient power. Likewise, many LED bulbs filcker when dimmed, though a number of newer LED bulbs have been engineered to dim for a portion of its output.